Night out gone wrong

It was the Christmas party from my office and afterwards some colleagues and I went to a pub. I was very very drunk and by the end it was only three of us. One of which I considered my friend and the other guy someone I previously had a thing with. They left to go to hers, didn’t even say good bye and I was just wondering around when a guy approached me. I don’t know how but the next morning, when I woke up I realised I ended up at his house. I feel so guilty and at the same time very sad. I shouldn’t have drank so much, but I trusted I was out with friends that would never do something like that. I feel very lonely and sad right now.