Spotting and Pregnant??

I am 30 years old. For as long as I can remember, AF has been 4-5 days, 28 day cycle, on time like clockwork. Past 2 months, AF is 3-4 days early, extremely light, and lasting only 1 day (if that). Husband and I have been trying to conceive for 6 months.. Pregnancy tests all negative. Should I be concerned?? Anyone experienced this??