Divorce amd too much partying

So, we just got back from this party that was out of town. This buddy of DH got divorced less than a year ago and was having a house warming party. He and his ex wife are still amicable. I barely knew them as a couple but I like both of them a lot. His ex wife wasn't at the party and it was CRAZY! I drank way to much.... I mean I passed out at 3am and still feel terrible today. I haven't done that it a long time. If we aren't pregnant this month I will totally blame myself since I am about 1-2DPO. Anyway the buddy if super sweet and huge flirt. I kept my eyes open for the one gal who was single and I found her. He introduced us and she is really nice. By the end of the night they were making out and yes in need she as there this morning before we all left. Not really sure what the whole situation it there but it's just so hard seeing him with someone else. Even DH said it just didn't seem right that the ex and his daughters weren't there. So not only am I hung over but I feel so sad about this divorce. They are the only people our age who I know that are divorced. Sigh! How bad is it that I got that drunk? I'm not even sure how it happened. I feel bad.