Has she found someone else?

Good morning everyone. I've got quite the story for you, hopefully it won't be too long. It's about the current situation of my relationship.
I'm a 22 year old guy that has been in a long-distance relationship for about 2 years with a girl living in Canada.
The past few months I haven't been treating her very fairly, and I have acknowledged that as work has stressed me out but I know that's not the best excuse.
Recently she brought up that maybe we should take a break.
And we did.

I couldn't do it though. After two days of thoughts and emotions tearing me apart, I had to break the break. I texted her saying that I miss her and I can change, and I will.
We started talking again like all was fine, it's amazing because I feel like it just re-sparked our relationship. I'm so in love and it's so much more powerful than ever before.
For me at least.

Since we're long distance we find things to do together to spend our time. Alas, we found the video game League of Legends and play that together exclusively as we talk through Skype. But I notice things are different ever since that break.
There will be periods of conversation where she will ignore me, as she texts on her phone. I ask her who's she's texting so late? She gets mad and says she isn't texting. Even though it's so obvious that she is. I can hear her nails as they hit the phone screen.

The other day I caught her in a small lie as well. We were talking through Skype like we always do, and her mom came in and she muted the microphone. When she came back I said, "Why did you mute your microphone?" She said "Huh? I didn't.. my microphone must be messing up." I called her out on the lie and she got really defensive, as if she's trying to hide something. She's been doing this exclusively every time her mom comes in as if she knows her mom could possibly bring up this "other guy" I suspect of.

Going back to the texting thing, she's quite the bad liar. I can hear her phone vibrate as she responds throughout the night. I call her out on it and she gets defensive, sometimes ignoring what I say until I have to repeat myself. Then she'll call me annoying.

Another issue I have is that she's recently been busy this week. And it's understandable for me, as she has valid excuses with school ending for her and things like that. However, there are still times of disappearance that she'll shrug off without explaining herself. It's driving me crazy. I hope that I'm not overthinking.

Recently, I've discovered that she's been playing the game League of Legends with another guy when I'm asleep or at work. I looked him up through Skype, and through Skype I found his Facebook. They live in the same city.
Since my career is a bit different, I'm not allowed to have a Facebook, so I can't check on what's going on there.

She still tells me she loves me, and when I bring up the possibility of her having found someone else, she shuts it down by saying there's no way she would do that, and "Who could I possibly be texting?". She says I keep accusing her and is asking when that's going to stop. We just ended our break on Wednesday and have been talking like this since.
I'm going out of my head guys.

So everyone, can someone please put the pieces together for me? Has she found someone else? Is there anything I could do to figure it out? Where do I go from here?
I love her to pieces.
Thank you all so much for reading this.