Re: idk what to do ):
The teen pregnancy board or the STD board might give you better answers but good for you for trying to get it all figured out. If you can't talk to your parents, how about another adult friend? Your body goes through lots of changes, especially if you're stressed out, which can cause weird symptoms or missed periods.
Remember, every time you decide not to use a condom, you run the risk of an STD, no matter how "perfect and clean" you and the guy both think he is. It's absolutely never worth it.
You can also visit any planned parenthood office and they're super nice and will help you with the chlamydia and a pregnancy test and birth control. It's all very discreet.
Hang in there. Being sexually active comes with a lot of strings attached but can be just fine if you take care of yourself and set yourself up with what you need to be safe and happy first. Love yourself just as much as you want to love that other person.