Period 2 times last month

bb

I had a period 11/2 and another 11/29 I was suppose to get my period 12/27 I believe and it’s still not here no sign of her whatsoever. But pregnancy test are BFN. I get a period every month since my miscarriage back in may. I’m not stressed or anything so I’m not sure what could be delaying my period if obviously not pregnant due to the BFN’s I’m still getting. Have anyone ever been through this. ?