Now he says he needs space!!! Should I just break up with him!

My boyfriend and I have been together for over a year last week I discovered a dating profile he had for a while (since before I met him) but I was curious and went to his msg. I found recent msg (like last week) where he flirted with a girl from the area ask to have sex when she said no asked for a date. It was way too familiar with how he asked me out. They exchanged numbers and ended their ( probably started texting instead) I didn't have a chance to look at his phone nor wanted to but now I am heart broken and don't know how to feel. He didn't deny it when I asked and came clean saying he been depressed which he has and he did an irrational thing. He said nothing happened from there but I have no idea whether he's telling the truth. I am now 10 days late for my period and I went to planned parenthood but they said I was negative I'm scared and don't know what to do... is what he did considered cheating? Could I be pregnant? What should I do?