<human>: I'm 16, he's 17. we've been dating for over 9 months

My boyfriend and I happen to be a couple of pretty mature beings. Last night however, I was extremely immature. All this month I have been extremely stressed over pressure from my sports, home, and school marks; he had been just brushing me off and not really helping me deal. 
I went to a party last night (without my boyfriend) and let go. Nothing went through my mind at all, so when one of my friends kissed me, I didn't even react. I just let it happen, and felt disgusting afterwards. I told my boyfriend today what happened, and he's devastated.
 I'm losing my mind trying to get him to understand that I'm sorry and that I want to work through it, but I need help. Is there a way to prove my loyalty to him at all? I'll hear anything at this point.

Give me the gist of the text in a nutshell
<bot>: kissed another guy at a party, boyfriend is in hysterics and so am I. Is there something more I can do to make the situation better?