About 4 or 5 months ago i broke up with my girlfriend. This must be a very cliched paragraph opener on this website by jow. Anyway, we were very close, but over the last month or so of our relationship, my feelings for her began to fade. I dont know why they did, they just did. I realised (with help from a friend) that it wasnt fair to her to let her continue putting that much into a relationship and get little in return, so i ended it. And so concludes the context of the situation.
Now for the character expositions. My now ex girlfriend had pretty bad anxiety. Im not saying this is the reason my feelings for her began to dissapate, just that she struggled with it and what i suspected to be mild depression. Now, she’s got a lot better, and she is making and maintaining new friendships which is wonderful.
I worry. A lot. And i guilt myself for things i shouldnt (hence this confession and why i’m lying awake at 1:56am).
After the breakup, we were both left in a bad way, but we did not want to just end our friendship right there and then. I considered her one of my absolute closest friends and she considered me the only person she felt really close to, for she struggled with her anxiety when it came to meeting new people and making friends (dont misunderstand me she did have friends but not as many as she would have liked, most were under her age and school year (like me), and not ones she felt very close to so overall she felt kinda alone). We agreed to not let the ending of this relationship come between us as friends.
Two or three times we ended up doing s***** stuff after the breakup due to a combination of teenage s** hormones and not wanting the relationship to be over. This will be important later so make note.
Within the past 2 months, shes made good friends with new people, which is fantastic. I’ am really sincerely happy for her and how shes progressed in fighting her anxiety. It also means she feels ok enough to reach out and meet new people. These are people who are her age and are just a good match for her.
Now we’re up to more recent times; within the last fortnight. We both went to a big party and she got really drunk and i got really high. At this point in time we are casual friends but for me theres a slightly tense undertone and a feeling of perilousness. After every time we ended up doing /stuff/ i felt it was wrong and we shouldnt do it, and i suppose this feeling of being on edge came from the risk of us doing something again. I thought that i was pretty much over her. If 100% was what i felt for her at the peak of our relationship, and 0% was just friends, i thought i was at 25%. Anywah, at this party (well technically before) i ended up kissing another girl. This was the first time i had ever kissed a girl outside of a relationship that wasnt my ex girlfriend. It was surprising and different, but it made me feel like utter scum. I hated myself because it felt like i was betraying my ex girlfriend (who im not sure if shes is fully over me). I shouldnt feel like this. I broke up with her why does it feel like im cheating on her. I spent the rest of the night trying to keep away from the girl i kissed and my ex girlfriend, due to this intense feeling lf guilt and nauseousness. I failed. My ex girlfriend was staying over at my house that night with another of our mutual friends so she didnt have to drive home. She was very drunk and she insisted on sitting with me and some of my friends. She was leaning on my arm and holding my wrist but she turned to me outright and announced that we werent going to have s** anymore which was a relief of sorts. It meant no more lying to my friends and no more feelings of guilt after. But during this meet up i felt so stricken with guilt i thought i was going to vomit. I made my excuse and left the party for a walk. I cleared my head, and returned to the party. When me and the mutual friend were ready to leave i texted her and asked if she was ready to leave too. She asked me to come and find her on the dancefloor, so i went up to find her. I arrived to find her dancing and grinding with another boy her age. Even remembering this event makes me feel sick. But it shouldnt. She has every right to dance with who she wants. But i feel ill at the thought. I turned away and texted her from afar, and she came over then we left. On the way home she drunkenly told us that she had told this boy that she liked him. Me and the mutual friend had suspected this for around a month, but the boy is in another relationship, but he may just like my ex girlfriend. We all came home and went to bed. End of main body of story.
Today i was in the gym, and i saw the boy she likes. I saw him and i felt horrendous.
Im scared shes going to forget about me

In summary, i feel guilty for:
feeling awful seeing her dancing with another, not wanting her to kiss someone else, me breaking off the relationship then not wanting her to be with someone else, kissing someone else, kissing someone else and feeling bad for it, not being over her, and for feeling guilty.
Even more summary: im scum