What do you think?

On February 19th my man and I had sex. Neither of us finished at all, we just decided to stop. No protection was used. My previous period app said my period was to come on March 6th. I still have not gotten my period. On the 6th I took a test in the afternoon and it came out negative. And another the next morning, negative as well. And this morning the 10th I took another test in the morning and it also came out negative. My period is usually in the middle of regular and irregular. So I may just be stressed out. Do you think I could be pregnant?