What Are The Side Effects Of Chlamydia Medications?

Hi Dr. I was tested for chlamydia and treated for it during this time I was put on an antibiotic and for the following week and a half me and my partner used condoms and then following that he never came in me. I also have used the pill for several months now and never missed one. I skipped my period this month and am due to have my next period in about a week and a half during this time period I have taken 3 tests all coming up negative. And a few days ago I had a single spot of blood and cramps could I be pregnant?