Well since you are still a teen, this topic can fit here as well.
In order for a home pregnancy test to be accurate you have to take it at least 2 weeks after having sex or after a missed/off period. If you took it before that, then it would give you a false negative. Anti-biotics do lessen the effects of birth control, so it is possible that you are pregnant again. Make sure to take the home pregnancy test correctly within the correct time frame. Don't discontinue your anti-biotics as that can cause the infection to come back worse and stick through with all of the doses. Though since you have already stopped taking them for a while, call your doctor to ask what to do about the remaining doses. If you have sex again in the mean time, use a back up method of birth control(condoms). Plus any time you start a new birth control or go on anti-biotics or other medications that can affect your birth control, you always need to use a back up method. Retest again with another home pregnancy test and see what it says. Other things can cause these symptoms, but it's important to find out if you are pregnant or not. Hope it all goes well.
im new to using this... this was actually supposed to go in the whole birth control section hmm