I Had Intercourse On Juky 4 And Started My Period

I had intercourse on Juky 4 and started my period on July 22-27 and it was a normal period, I was going through tampons like crazy. I did not have a period in August and it is now September 24 and I still have not had a period. I've taken 5 pregnancy tests all at different times and they are all negative. No symptoms and I don't look like I e gained any weight or like I am even showing. Could I still be pregnant?