Loss at 7 weeks

I was 7-8 weeks pregnant and experiencing some bleeding. I called my doctor and went in for blood work on a Friday and returned Tuesday for follow up blood work. I received a phone call on Wednesday the my HCG levels had dropped and that I would have a miscarriage. I naturally miscarried on Saturday morning with huge clots and horrible bleeding. My doctor wants to follow up with me in 4-6 weeks is this normal? Should I have had an ultrasound? Just want some advice. Any would be greatly appreciated. Thank you in advance.