I had unprotected sex 2 weeks ago and I am still bleeding. There's no pain, but I have no idea what's wrong or why I'm still bleeding. Could I be pregnant? Or have tearing? Or have gotten an STD? I am on birth control. I am 18 years old.

Two weeks of bleeding? I'd have made a trip to the doctor, or your gynecologist. THere are a lot of possibilities... I think a tear or fissure is most likely.

Keep in mind STD's are always a possibility... only condoms provide any measure of protection against those... and they are not foolproof and only about 80% effective.

Use of condoms in conjunction with the pill will reduce the chances of pregnancy further from just the pill alone. No form of birth control is 100% effective. Also I suggest condom use as well at your age because approx 28% of the youth are infected with HPV... which can cause cervical cancer and not just genital warts. Its not always visibly obvious who does and doesn't have it.