Maybe Pregnant?!? Help!

Amy
I'm not someone who tracks her periods very often but I think if I ballpark my last period was at the end of August. I never had one for the month of September and so far for the month of October I haven't had one either (and the month is almost up). I have taken two pregnancy tests weeks apart just in case and they were both saying negative. I have not had any symptoms of pregnancy. At all. But I am kind of getting worried here. Any suggestions?