Is this a normal failed dating experience?

Basically there was (is) a girl from my uni. Things started well, as she kept making eye contact in our class. She initiated this as I am shy and don't like staring at girls. Eventually we got talking as she knew this other girl I know and we were all in the pub one night. We got on okay, she seemed kind of shy though, but it turns out we both live in London, about half an hour away by public transport. In May she then had a party at her house and I was invited but it didn't go well. I got sick after drinking punch through no fault of my own and had to lie down in one of the bedrooms for a while. She came into the room and I told her to go away, I actually said F off, I have no idea why though, it was more the alcohol talking. I eventually staggered home and that was that until last weekend. Uni is now over and I am in London and I went to my supermarket and saw her there. I was going to say hi but she looked at me blankly then ignored me and I saw she was with a guy. I saw them leave the supermarket together. On leaving the supermarket about 5 minutes later she was stood right outside the exit snogging this guy in front of me. I walked off feeling very, very embarassed. How could she do this, how could she be so mean. If I see her again in any of the pubs around here I'll probably break down and cry to be honest.

I must be missing something, because I'm not sure how this was a dating experience at all. A girl you liked invited you to a party, where you proceeded to get drunk and swear at her. Nothing else then happens until you see her with another guy, who she presumably is actually dating. I don't think it's overly likely that she was kissing this guy in front of you deliberately. She did not ever date you, and even if she liked you and/or assumed that you liked her, your behaviour at the party appears to have ended any hope of that.
To answer the question, yes, people making fools of themselves, thereby ending romantic interest from someone else is pretty common. Even before that happened she didn't owe you anything, and she certainly doesn't owe you anything now. As much as you may have been pinning your hopes on this girl, almost literally nothing happened in real life to progress this beyond friendship. You really need to move on.

I texted her after the party to say sorry, she said that's OK see you around then, that was at the end of term and I didn't see or hear from her after that. I got drunk at the party out of nervousness tbh. If I run into her again in one of the pubs around here or anything I'll keep it friendly but I'm not texting her tbh. I do think she did it deliberately, to demonstrate she is now taken but it was kind of a harsh way of doing it in a way but that's just the way it goes I guess.

Basically there was (is) a girl from my uni. Things started well, as she kept making eye contact in our class. She initiated this as I am shy and don't like staring at girls. Eventually we got talking as she knew this other girl I know and we were all in the pub one night. We got on okay, she seemed kind of shy though, but it turns out we both live in London, about half an hour away by public transport. In May she then had a party at her house and I was invited but it didn't go well. I got sick after drinking punch through no fault of my own and had to lie down in one of the bedrooms for a while. She came into the room and I told her to go away, I actually said F off, I have no idea why though, it was more the alcohol talking. I eventually staggered home and that was that until last weekend. Uni is now over and I am in London and I went to my supermarket and saw her there. I was going to say hi but she looked at me blankly then ignored me and I saw she was with a guy. I saw them leave the supermarket together. On leaving the supermarket about 5 minutes later she was stood right outside the exit snogging this guy in front of me. I walked off feeling very, very embarassed. How could she do this, how could she be so mean. If I see her again in any of the pubs around here I'll probably break down and cry to be honest.

Basically there was (is) a girl from my uni. Things started well, as she kept making eye contact in our class. She initiated this as I am shy and don't like staring at girls. Eventually we got talking as she knew this other girl I know and we were all in the pub one night. We got on okay, she seemed kind of shy though, but it turns out we both live in London, about half an hour away by public transport. In May she then had a party at her house and I was invited but it didn't go well. I got sick after drinking punch through no fault of my own and had to lie down in one of the bedrooms for a while. She came into the room and I told her to go away, I actually said F off, I have no idea why though, it was more the alcohol talking. I eventually staggered home and that was that until last weekend. Uni is now over and I am in London and I went to my supermarket and saw her there. I was going to say hi but she looked at me blankly then ignored me and I saw she was with a guy. I saw them leave the supermarket together. On leaving the supermarket about 5 minutes later she was stood right outside the exit snogging this guy in front of me. I walked off feeling very, very embarassed. How could she do this, how could she be so mean. If I see her again in any of the pubs around here I'll probably break down and cry to be honest.