I've been taking my pills (Lo Loestrine Fe) on time/ everyday for 3 weeks. Last night I had unprotected sex (took my pill yesterday) and this morning I was put on antibiotics for a tooth ache. ... I know that for as long I'm on the antibiotics and at least a week after I'm done with the antibiotics that I have to use condoms. My question is, am I protected from last night? Do I have to worry about getting pregnant?