My Emotionally Unstable Boyfriend Broke Up With Me?

This relationship was the best one I had in my whole life. I could wholeheartedly say he was my first love. He was sweet and wonderful and always made me feel wanted and good about myself. I hadn't felt good about myself in a long time before he came along. For once, I felt happy and not bored with my life. It was perfect.
He had told me that he was slightly depressed, but he reassured me that he needed me to get through it. He told me so many things, like how I made everything better and how he could never imagine leaving me. Everything was fine.
Literally, one week we were great. Over the weekend, however, he was very bland over text. I asked him what was wrong and he claimed that he was upset about a few things and didn't want to talk about it. I didn't push it.
On Monday, I saw him again, and he was very distant. The next day, he opened up a bit more and acted more like his normal self, but was still distant compared to how he usually is. That is also the day he chose to dump me.
He told me that it wasn't my fault, he's just going through a lot and it would hurt him to drag a "perfect person" like me down with him. He told me he still loved and cared about me. He told me he still hoped we could be friends and I put on a show and smiled and said, "of course."
He texted me after we parted as well, telling me that he just needs to go through an "emotional and psychological detox" and he just doesn't want me to be a part of it all. He asked me if we were still friends and I again said, "of course."
The next day, however, he completely ignored me. We haven't said a word to each other since. We see each other four days a week, and he completely ignores my existence. We haven't even made eye contact.
What's wrong? I thought he wanted to at least remain friends?
After this breakup, I feel broken and worthless. When I'm around people, I'm fine. I laugh and all, but he's still at the back of my mind. It's awful. When I'm alone, though, thoughts of him overwhelm me and leave me sobbing into a pillow or something of that sort. I hate this. Before we dated, I was completely fine. Why can't I be fine now?
Does he really actually still "love and care about me"?? Or was that just an easy way to get out of the relationship? Where did I go wrong? How could he just ignore me like this? Was our relationship just a void of empty promises?
The worst thing is, he seems fine. Not upset at all. Laughing with his friends and all.
I just want some sort of explanation. But most of all, I just want him to come back. I wish he'd come back and tell me he misses me. How could things change in the matter of a week?
A friend of mine and him had actually texted and he told him he still "loves me" but he's just going through a hard time. How can you ignore someone you love?
It's been about three weeks since we've broken up and not said a word to each other. It hurts me so bad. I don't know how to bring him back or whether to know if this is actually completely over. How can I get him back?