Spotting

      Around January of this year I had a miscarriage and had a d/c performed. I had  3 normal cycles after but in May did not have one. My last cycle was the last week in April. Then a week in a half later had spotting for a couple of days. So, I called my doctor he examined me and said everything was fine. Then another week and a half later I started spotting again so I was sent to get an ultrasound and came back with a thinking uterus lining. My doctor told me it could be Bc I didn't have a period in May or that I could be pregnant. So I took a test it was negative then I started my period on June 6 and last till the 9. It was normal. I was relieved Bc I thought my body was going back to normal. Unfortunately, I just noticed spotting again this morning. I'm very confused and worried. I've never experienced any irregularities before this. Any advice or knowledge would be very helpful! Thanks :)