I was on Trinessa Birth control for about 8 months or so and I had been taking it late and that month I took it one week late & when I got my period it only lasted 3 days and was very short. The next month I stopped taking the poll completely and I didn't get my period at all & the day I was supposed to get my period but didnt but I got the Depo shot & I had unprotected sex yessterday. it's been about three weeks since I haven't gotten my period and I was wondering could I get pregnant bcos the depo shot may not be in effect yet?