Cramping

I am somewhere between 4-5 weeks pregnant. I am having some vaginal/pelvic cramping sometimes. So far, with 2 blood work, my HCG is doing a little more than doubling, I went from 34 Monday to 219 on Thursday. This is lt first time pregnant. What kind of cramping pain is normal for this point in pregnancy? My doctor takes forever to reply and I would like to know opinions from others who are currently pregnant or have been pregnant before.