What should be my next step?

I’ve always had a very regular period. I had an abortion in June at 7 weeks and had an IUD put in, even after that i got pretty regular periods. I had the IUD taken out end of September, and had a period in October and November, but this month AF has just decided to go into hiding, she was supposed to come Dec. 18. I’m definitely not pregnant, according to plenty of HPT’s. Could it be that my periods are still regulating themselves after IUD removal? Any insight is appreciated, and please no negativity or judgment.