Hello Jackleburger,
It could be the utrogestan that's causing the cramping, I've had similar feeling with it . Sometimes a side effect can be loose bowels &cramping too .
If you're worried before your appointment, maybe call out of hours docs for advise ?
Hopefully it'll settle down for you with what you're doing. It's funny was going to say drug ,but it's not!(hormone) &can take a while to get used to it .