I was supposed to start my period February 17th, it's now February 21st which makes me 4 days late, I went do the OBGYN on February 8th and she took a urine sample and I found out I tested positive for chlamydia on February 10th, but I was treated for it with azithromycin the day I found out I had it. I was on Loestrin birth control for about 8 years but I stop taking it in December so I thought it would take my body a long time to adjust back to a normal period but I had a period that lasted 10 days in January. Am I pregnant or could it be something else?