I recently pulled a very beautiful girl I had fancied for ages on a night out and we ended up going back to her place.
I’d wanted to nail this girl for months so I was under a bit of pressure to perform. After some awkward fooling around and uncomfortable sex I was spent.
WTF? After doing something like that, she probably thinks you just wanted to get in her pants for a one night stand. If you really want to get together with her for any kind of relationship, you need to tell her that you're serious about her. She probably won't believe you after doing something like that. Girls are sensitive about sex and everything surrounding it.
I can't believe someone would actually do that, but #2's advice seems sound.
You've blown it. For both your dignity, move on.