Could I be pregnant?

Dec. 17, 23, 25 as well as Jan. 2nd I had unprotected sex with my boyfriend he cummed in me every time, during December the days we did it was 2 weeks before my period, I read you ovulate 15 days before your period. Anyways I got my period for January and February but it's extremely light and I have always gotten them Heavy Heavy, there was also a point where I got really sensitive towards everything! With that in mind I started smoking Jane after my first period and have been ever since that day but recently my boyfriend and I tried again on Feb. 18 5/6 days after my period. Is it a possibility that I could've been pregnant even while having my period? Or that I am? I took like 2/3 pregnancy test and they all came out negative