Does Antibiotics Taken For Bladder Infection Alter The Pregnancy Test Results?

okay, i am on birth control. so me and my bf have unprotected sex. i missed my period so i thought i would take a p test and it was negative. ive been taking antibiotics for a bladder infection and the pills say that they may alter urine tests. so im wondering if the test was wrong? also, sex is always painful to me. really painful to me and its not very pleasurable. ive been taking extenze for women but its not helping. what can i do?