6 weeks- spotting and cramping

Charlene
Hey ladies, I'm 6 weeks along and I've been having dark spotting and cramping (not very bad, just feels like light period pains with a bit of backache). Anyone else experience this? How long does it last? Doctor has pescribed progesterone.
I'm a bit nervous cause I had a miscarriage earlier this year, so the spotting and cramps brings back some bad memories!