Cramping

Hey ladies. My hubby and I have been TTC since Feb. and I got BFP today! I would have bet my life that I was going to start my period. I spotted Thursday and have been having continual cramps since then as well. The cramps haven't been as bad as period cramps. They are just kinda dull and achy. I have read stuff online saying it's normal and my doc told me today that it's common. I've had two pregnancies prior and I didn't cramp like this. Just a little worried. Any of you ladies experienced this as well? Thanks!