Day 20 of cycle. cramping in front and lower back since last night. moderate pain w/ severe peak this morning. could this be implantation or a cyst?

Possibly cyst: Implantation may cause some bleeding but isn't painful while ovarian cysts can be quite painful. Clomid (clomiphene) can cause painful ovarian hyperstimulation. However, I don't understand why you're on OCP's concurrently. Given your moderate to severe pain and history of miscarriage, you need to see a doctor. While your OBGyn would be ideal, it's more important that you see someone promptly.