I am a sexually active woman and I am 3 weeks late on my period. I've taken 3 at-home pregnancy tests, all of which have turned out negative. Now, I am one of those people who have irregular periods, but I've never been this late. I'm very scared that there's something seriously wrong with me, but I don't want to get myself that worried until I can rule out other issues I have had in the past.

In March I got a really bad urinary tract infection...so bad that I was peeing blood. I got another one in early May. Could this have messed up my period?

Also, I've been having low blood sugar troubles. Does this also interfere with your period?