On antibiotic for uti and having breakthrough spotting while on bcp's. i'm otherwise healthy. can i double up on by pill for the next few days ?

Don't double up: You should take the prescribed medication as directed and not double up. Make sure a urine culture was obtained. This will assure that you are on the correct antibiotic. The antibiotic could be affecting your birth control pills and I would strongly advise that you use protection during intercourse until the next cycle as the antibiotics may make the birth control pills less effective.

Add a condom: The package insert from the bcp, which you can see online will say if you need to take abx, the bcp may lose effectiveness, so, use a "backup method" in addition to the bcp. It's a good idea on general principle to use condoms anyway, as they help decrease the chance of an sti. I never said, or heard it said to double up on the bcp. The condoms should be used 4 2 wks. Good Luck