Ex boyfriend advice - Guys I really need your advice

I'd not been dating this guy long (about 5 weeks - and yes we slept together once during this time) when it all fell apart.

Both of us are pretty impulsive and within a week he was declaring us 'boyfriend and girlfriend' which although I thought fast, I was so happy to go along with him as we got on so well and the attraction was unlike anything I'd experienced in a very long time.

We work for the same company but different offices and he didn't want people at work to know of our relationship. I agreed as I wanted to keep our personal and professional lives separate.

After 3 weeks of dating it was my 30th birthday and I invited him to attend. On the day of my birthday he text to say his Dad had had a minor accident and he was going to be late. I replied to say 'no worries' and do what you need to do etc. All was good. Then, about 3 hours later, I received another text to say 'sorry, you're going to hate me but I can't make it. We'll do presents and cuddles on Monday' (two days later). I tried to call but no answer. The rest of the weekend I didn't contact him and didn't hear from him. Monday came round and he text to say 'you talking to me yet trouble?' I was a little miffed tbh and just replied to say I'd see him later as we were meeting for a work event in the evening.

During the evening I took him aside to just say I was disappointed he couldnt make it but kept it quite light and afterwards we enjoyed the evening. Now work colleagues were there and although he said he didn't want people to know about us we were joined at the hip all evening, holding hands etc. Tbh I didn't even think about it, I was just so happy we were enjoying such a wonderful evening together. (btw the presents didn't materialise). I did find it a little strange that we talked about 'slowing things down' and I was actually really pleased he brought it up but as you've just read the rest of the evening we were pretty much inseparable!

The following day we met and had lunch which was really lovely and I felt we were back into having a fab time together (still no presents - and its not like I want things I just thought it was bizarre how he'd missed my birthday but then didn't do anything to follow through with his promise).

The rest of the week was a little weird in that I barely heard from him and but when I did it was really pleasant. I'd planned to go home for the weekend to celebrate my birthday with family and was a a little hurt he hadn't messaged to say 'have a nice time'. Nothing for the next 3 days so I decided to call and ask why I heard so little from him (perhaps to confirm my suspicion that perhaps he wasn't that interested after all) . No answer on both occasions so I figure 'this guy just isn't that into me' so I ended it by text (I hated doing that but I felt like I needed to take some control as he hadn't answered and it felt like it was getting really silly especially as I'd never dated someone who contacted me so infrequently)

The following day I received a message to say he was stunned and didn't know what to say so I suggested we talk about it rather than text back and forth.

Before we even had a chance to speak I received a long message to say I'd been telling people in his office about us. One of the girls had asked me whether I'd seen him the weekend of the my birthday and I just didn't think and told her I hadn't seen him as he couldn't make it (no more or less than that). Anyway he was pretty pissed even though I know he'd told his boss about us and was blatantly flirting with me over the phone where everyone in his office knew he was talking to me. I feel like he gaslighted me! (new term I've learned) I finally sent him a message to say if I could forgive him for not attending my birthday then surely he could forgive me for accidently telling his work colleague. I also said it we could draw a line and go back to having a professional working relationship that would probably be best. I ended the message on a positive note telling him how much I enjoyed our brief but wonderful times together and I would always cherish those memories. Guess what - no reply.

After that we didn't talk for about a week until he called to discuss a work presentation. The call was bizarre to say the least. We probably talked about 40 minutes about how we were and he'd asked about a play I'd seen with my friend (he'd read that on facebook). We laughed and joked as if nothing had happened and afterwards I sat there stunned completely shocked at how amazing it was for us to talk the way we did. Anyway, the presentation came round and I was told by several colleagues (who didn't know about us) that he was looking over at me smiling and a number of times he came over when I was talking with other associates. My colleagues said he was like some lost puppy although I didn't personally notice - well I was trying to remain professional and keep our ex-relationship at the door. There was an instance whereby I'd asked him to pass the glass of water from the side table next to where he was. He said it was his and that we could share. I know this is a minor detail but I wouldnt usually just share a glass with someone without either being close to them either as family or close friend. As the conference had started I just agreed and we sat it between us on the floor. (Sorry that's a bit random)

We left the event together (basically I left first and he came after me) and again I felt this pull towards him. My heart sank as I recalled the way he'd treated me re my birthday and afterwards and yet I couldn't help but think about the brief but wonderful times we'd had on dates (he was always so attentive but not erm smarmy or flash just nice), talking on the phone etc. He left me at the end of the road as we were walking in opposite directions. I couldn't be 100% sure but he seemed to be hinting for me to walk with him but I didn't want to look like a complete tool so we said our goodbyes.

Since then we've talked for work but nothing more. When he calls though he's so familiar as in that I'll answer and he'll say 'hey it's me!' and I just carry on the conversation only discussing work. I get the feeling he doesn't know what he wants and yet it still upsets me now - 4 weeks on. I'm 13 days into no contact (other than the odd work call or email) and I know I should probably walk away but I've honestly not felt the way about a man in at least 3 years. I was going to follow a 30 day no contact and see how I feel after that.

I'd like your honest opinions as to how I go about contacting him (I was going to go the text route) but I don't know what to say or 'ask' when I do reach out?!

Also, IF he contacts me do I just ignore it while I'm going through the no contact period or is that just silly?

Many thanks guys, I think this definitely requires a male perspective