About two weeks late.. Can I be pregnant?

me and my boyfriend have had probably about 6-7 times since the 9th day of my 28 day cycle. my last period started on may 15, and i should have started again on june 11, and i kept thinkin it would come, it just never did. but on the 9th day of my cycle, he came inside me. is there any possibility i could be pregnant? ive taken like 3 pregnancy tests. but they were all negative. and the first time i was pregnant it was negative until i was about 3 months. im going to the doctor on tuesday to get a blood test. but what do yall think, could i pregnant? if not what else could it be. i know this is long, im just kinda stuck in a rut. after my first pregnancy its been hard gettin back on my feet again, and im startin college finally in the fall. i just wanna know..