How do I go on?

So I've been dating this amazing guy since December. We lost our virginities to each other. Anyhow. I hung out with a guy friend recently that I hadn't seen in a long time. He knew I had a boyfriend and I told him I didn't want anything to happen because I love my boyfriend. We were strictly just going to hang out. Well the night went on and he ended up pulling my pants down while I was saying no and i was trying to pull them up. But let's just say he's a LOT stronger than I am and he ended up fingering me and kissing me. Guys. I'm balling my eyes out and I can't stop. I feel like I cheated on the love of my life and I didn't want to. Maybe I could have done more to stop the guy? I just wanted to catch up with him. But nope. I'm sorry if everyone now is going to label me as a slut. But what can I do? I feel like I have to break up with my boyfriend now. He's going to be so heart broken because I know I already am. Ugh. If anyone can give any feedback please please help.