late period

Ok, so I am 5 going on 6 days late.. I'm usually ALWAYS on time! I have taken 4 test 2ept 2first response.. all negative! I had a miscarriage in November (my first pregnancy), and I've had 3 normal cycles since.. I started to have a little cramping today, but not normal period cramps.. very light ones.. breast are so sore! When should I take another test or skip the HPTs and go to the OB