Progesterone and cramping?

Hi ladies, I'm 8.3 with our little bean. I had blood drawn a couple weeks ago bc I have a history of low progesterone and early mc's. Anyways, it was low so my dr. started me on sublingual progesterone drops... had my blood drawn again 2 days ago and it's still low so he doubled my dose. I've been having the worst cramping ever since I took my first doubled dose tonight... does anyone know if it's normal for progesterone supplements to cause cramping? I'm trying not to freak out over here bc everything is closed for the holiday weekend, but I just want to have another ultrasound and see a heartbeat again!