Heavy cramping 3 weeks pregnant...

I'm 3 weeks pregnant and I've had cramps since I ovulated but they have always been I'll and infrequent. The last few days though I've been having episodes lasting a few hrs where there.full on painful period cramps and last night they actually woke me up they were so bad! I have not had any signs of bleeding what's ever yet though.. Is this normal? I have a Dr's apt in a few weeks.