I'm not a medical doctor by any extreme! How bad are you cramping? it could just be uterus doing things, you know, mama things. :) When I was implanting with my first pregnancy, I had crazy cramps... when I found out I was pregnant, I had mild cramping and spotting. when I got my first ultrasound, I was so early on they couldn't detect a fetal pole. They asked me to come back in 4 weeks to determine if the pregnancy was viable. It was in fact viable... the 4 weeks I waited was insane!!
2 months ago, I think I had an early term miscarriage. I had been trying with DH for 5 months at that point, hadn't seen a positive test yet, but had EXTREME cramping, chunky brown discharge, and I was extremely tired. This followed with about a week of heavy brown discharge, very chunky. It could have been confused with my period if I hadn't paid attention to how I felt. Now, I'm starting my 8th month of TTC and I'm not pregnant yet. Still waiting.
So pay attention to your body. How do you feel? Either way, if you question anything, see a doctor on monday who can help you get the answers you need! In the mean time, take it easy if you can. Don't over exert yourself if possible.