Could I be pregnant?

I'm on the birth control pill Lutera (a generic version of allesse) and I've been on this birth control for a year now.
In my pack the white pills are the ones that administer the hormones to keep me from ovulating and such, and then my pink pills are my placebo pills.
This might sound confusing to most, but I'm kindly worried at the moment about possible pregnancy.
You see, not on my current pack, or the pack before, but 2 packs ago (on the placebo week) I took antibiotics. I took them for 3 days and was through with the medicine before my period ended. I then took 2 full weeks of the next pack and had unprotexted sex. Then took the rest of my pack (2 full more weeks of the white pill) and had my period again. And then at the beginning of this last pack I started trying to change the time I took my pill, but after the first 2 days I have up and just stayed at my regular time. But it was also at the end of this first week that me and my boyfriend of a year had unprotected sex. Quite a few times (please don't judge me). But he never got off in me. And I do understand pre-*** can contain sperm. But I'm just wondering if I could be pregnant. I'm still 1 white pill away from starting my placebo week for this pack. I'm thinking that I'm psych-ing myself out and making myself think I have symptoms because of the stress. But I just want opinions.
I have taken 2 pregnancy tests this past month. Including one this morning. They both came out negative. But like I said, I'm wanting to know opinions.
Comments and advice are GREATLY appreciated.

[Arti Sharma, M.D.]

Hi there,
Few antibiotics may affect the efficacy of the birth control pills and if you have sex during that time you may need an additional back up method like condom to prevent pregnancy. It seems that you have been taking your pills regularly .It is possible to become pregnant from a man's pre-ejaculate fluid under few circumstances though the chances are quite low. If there is any sperm left behind from a previous ejaculation it may result in pregnancy. Taking pills regularly and on same time everyday prevents against pregnancy. You are having your periods regularly and pregnancy tests are negative so there are no chances that you could be pregnant. If you are still concerned do consult your doctor and clarify your doubts. Keep me posted with more queries.
Best wishes and take care!