Crystal,
I think that if you managed an hour and a half before there were any problems then you did pretty well. Being in crowds is something that I have gotten better with. At first I would go to a party and literally stay for 10 minutes. I can manage longer now. The trouble is that if I leave when I am getting symptoms, it is probably too late and then I will need some recovery time. Perhaps you could try shorter parties and then build up.

I am not sure that it is just the volume of noise that is the problem, but noise doesn't help, so if ear plugs are of benefit to you then go for it.

I quite often use ear plugs when there is loud noise, and no one even notices that I have them in. They are difficult to see from the front, and, if your hair covers your ears then they are completely concealed.

Concussed Scientist