i had a miscarage on boxing day now i have lower back ache w

i had miscarage on boxing day night i was 9 weeks went for a scan the next morning and was told there was no sac i think i passed it not sure i have had blood tests and my hpi level went from 6500 to 1800 and due to have another on friday just in case its not in my tube but now i seem to have a lower ache in my back is this normal