Cramping and sore boobs...

Hello ladies. I need your opinions!

I had a miscarriage 3 weeks ago..I bled for 6 days. Glow says I should be ovulating in 3 days but I’m not sure about that because of the miscarriage. So since yesterday I’ve been having this cramping that does not feel like period cramps and they are causing lower back pain. Also, my boobs are super sore and that never happens, not even around the time of my period...what do you think that could mean? Have any of you had this before?