Any chance of pregnancy?

Kind of a complicated situation. I took anti biotics. I am on birth control. We had sex twice (protected) while I was taking the anti biotics. And then twice with the pull out, and twice with no protection at all. Now my period is a day late. I am having brown spotting, bloated, maybe a bit nauseaous but that could be from being so nervous, a bit of cramping sometimes. I took several tests. Some were negative, some i could see a bit of a line but not 100%sure and they didnt seem to have color so I thought it was negatives for sure. But now im wondering if there could be a chance i am pregnant? I have a 3 year old, it took us 9 months to conceive, we were not trying, my husband will freak tf out if i really am pregnant.