Missed period- negative test

Hi I’m new here. I was wondering if anyone had experienced the same as me. I had a miscarriage in October 2018 at 6 weeks, my cycle seemed to go back to normal once mc was complete and I had a normal period at the beginning of December 2018 (2nd December). My cycle is usually 30-32 days and regular so I was expecting a period beginning of this month however still no period. I don’t feel pregnant at all no symptoms or anything and I’ve been pregnant twice, one resulting in the miscarriage last year and the other 7 years ago when I had my little boy and I’ve done two tests that came back negative so I don’t think I am pregnant.

I have been having cramping pains a bit like period pains but mild on and off for three weeks and about two weeks ago I had a really dull ache type cramp in the left side of my lower back that lasted on and off for about a week. I wondered if anyone had experienced the same sort of thing and if they eventually had a period?

It just concerns me that I’ve missed a period and worries me that the cramps and the lower back ache may be due to something wrong with my body after the miscarriage?

I spoke with the epu last week she said that I should monitor the pains and take another test in a weeks time but I don’t see the point in doing a test when I feel like I know that I’m not pregnant. She did also say that the miscarriage could have caused irregular periods and messed with my cycle.

Anyone who has experienced the same who could tell me what happened to them would be a great help.

Thank you