Scared I Might Be Pregnant. Please Help!

Symptoms of pms & of pregnancy can be very similar. If you're really stressed out you can take a pregnancy test but I can't really tell from your post if your period is late yet or not. I know you're having breakthrough bleeding but it's all about the timing. A pregnancy test will detect a pregnancy usually by the day after you expected your period, if you test too early you could get a negative result but still be pregnant.

Implantation bleeding only happens to some women, I believe it's normally lighter than a regular period and can happen earlier than you expect your period, but breakthrough bleeding while on the pill would have similar symptoms.

If you're really unsure go back to planned parenthood, tell them you think you may be pregnant because the antibiotics you took could have affected the pills effectiveness and you weren't using back up birth control and see if they'll do a blood test, (sorry I don't know much about planned parenthood, don't actually know if they do blood tests) a blood test will tell you sooner than a urine test if you are pregnant.

Thanks for the advice. do you know how long implantation bleeding generally tends to last?

From what i've read and what others have posted anywhere from an hour to a couple of days, and I don't really know how many of those posts were actual implantation and how many were early periods or breakthrough bleeding.

Implantation bleeding is one of those things that in hindsight, after you confirm you're pregnant, you can say...Oh yay, that must have been implantation bleeding!