Talk to Gynecologist on IVF C 5000 Iu In 5th Week Pregnant

I'm pregnant but it didn't show on ultrasound as fetus age is just 5 weeks, I had clots in previous history and Dr think that was so so early miscarriage and it was too weak. so now she gave me IVF c 5000 inj to avoid such issues...but I feel back pain after injection even though I was good before it..she said to inj again after a week so what should I do?