QUESTIONS— PLEASE HELP! 😭

Is my cramping normal, what does it mean if so? How long will I get opk positives? When should I test for HCG?

I am on cycle day 18. Yesterday I received my first positive opk. I tested this morning with FMU and it is still just as positive. I take Metformin and a Prenatal daily. I took Medroxyprogesterone to start my cycle and Letrozole on CD 3-7 at 7.5MG. I have bloodwork coming up on CD 21 and 23 to make sure I ovulated. But all today, I have been cramping. It’s not a sharp pain but a HORRIBLE achy pain that just seems to get worse the more I move. It’s on both sides, not just one.