Strong cramps during bd while 5 weeks prego?

So the hubby and I were enjoying our selves last night and tried some of our usual moves and I started getting some pretty strong cramps. It wasn't the worst I've ever felt (more like the beginning of the 1st day of af) but it kinda scared me. I've been getting fairly light cramps throughout the day, on and off since I got my bfp, but they never felt like that. After we finished, 2 minutes later, the cramps were gone, and I haven't felt them like that since last night. Like I stated, I'm 5 weeks along, and just wondering if anyone has dealt with that. Is it normal? Should I be worried?