First I want to thank everyone who's replied. It really means a lot to me--I'm not sure I can even tell you how much.

@Snark
You were taught that what you enjoy is wrong. It's hard to unlearn something that was pounded into you from an early age. It's more wrong to beat yourself up because what others have said is "wrong" is what you enjoy.
This probably is a big part of it. I just don't understand how I can understand and honestly believe it's okay for other people but not for me. I guess it's something I just need to work on, though. It means a lot to know that I'm not weird and strange in the world of weird and strange. :P

@Thir:
In my organisations we discussed a thing we called 'overdose'. It happended with especially new people, who would get totally ovewhelmed very quickly and feel real bad about it all, even, in some cases, a little sick. Apparently for their own individual reasons they reacted very strongly to everything.

I guess the only remedy is to accept that this is the case, and then make sure to take things in very, very small steps.
I'm glad I'm not the only one! In my case, I think it gets further exacerbated by my tendency to obsessively submerse myself in the site. As interesting as this all is and as much as it draws me, I guess I really do have to take things slow. It's hard, because sometimes I just *want* things so much, but I don't want to really upset myself either. It's also very reassuring to know that the way I'm reacting to even just this website is normal (or at least normal-ish); that makes it less scary.

@DeityorDevil
The best suggestion I can give you, is to check in with your feelings very regularly. If something starts to feel scary or overwhelming, take a step back to breathe for a minute, think about what you're feeling and where it's coming from. Is it a reaction to something someone said? A reaction to your response to something you read? Write it down, if that helps you to feel clearer about it. Think about what function that emotion is having for you.
This is really good advice! Thank you. I mean, it seems like common sense and all, but when I get upset or scared, common sense tends to fly out the window. Having had someone else who's not me tell me to remember to take a step back and breathe I think will be really helpful.

@ami_r90
Remember you have support here on the forums in whatever ways we can help, and I hope we can!
I'll try! Everyone here has been so nice and supportive, which really goes a long way in making me feel more comfortable. I see what you mean about the labels--I do kind of wish I could label myself so everything would be easy and packaged up, but on the other hand, labels are definitely for cans, not people.

Thank you all again. So much.