In some situations I'd say a good one night stand would do wonders, but I don't think it would help you. I think it would make things worse as you seem like the kind of guy who would get really attached immediately.
Sure, talking to girls on the internet might be a confidence booster, but it's completely different from real life and could give you unrealistic expectations of how things work out there in the offline world.
It sounds like you end up in lots of situations with regular girls, like that party you went to on Friday night. All is not lost, man! Calm down, don't worry so much about getting a girlfriend and have a good time. If you see someone who seems cool, ask her for her number or if she wants to get a drink sometime. If she says yes, good job! If she's no, at least you tried and you can move on. Your world doesn't end and giant robots still rule.