I'm pretty confused about what's happening. Please help?!

It's highly unlikely that you're pregnant from what you're saying. Condoms are 98% effective and birth control about 99%. Plus he didn't ejaculate even.
Brown blood is probably just light spotting (older blood instead of fresh and fast flowing bright red) and could be signs of a a period. Plus, a lot of birth control greatly diminishes a period to almost no bleeding at all.

I really wouldn't worry.

However if you still don't have a proper period in a few week's time, take a test just to be sure.
Though it's practically impossible to be pregnant from what you've described.

if you have blood in your underwear, its likely old blood, and so you can deduce that you are most likely not pregant, unless you have two wombs or something. Your symptoms are common ones of a period anyway, so i shouldn't worry. You are probably just paranoid what with it being your first time, and being nervous you might be pregnant.

if you honestly have taken all those precautions the chances of being pregnant are pretty slim, I would think you are eating a lot because you are nervous about having sex and the chance of being pregnant, also your period can be affected by nerves. I think you are scarring yourself over nothing.

Sounds like you had safe sex so it might just be something else going on with your body - changes in hormones, diet, stress, etc can all cause changes in your period. Don't freak yourself out - everything seems to be fine and I highly doubt you could be pregnant!!!

If you are still having your period you are NOT pregnant

Hm. I think there's a 25% chance you're pregnant. Of course the only way to know is to take a test. Good Luck! :)

You aren't pregnant, just very paranoid. If all of this has happened before, then there isn't anything to worry about. And symptoms of pregnancy shouldn't occur until weeks after the actual conception occurs. Also, if you received your period, that alone should give you little to worry about. At least, I think it should.