Positive test 5 weeks after miscarriage

Lo
Hello everyone, possible trigger comment ***
I am 5 weeks post miscarriage and surgical removal. I still haven't had a period so went to docs who did blood work my hcg is 90.... Sending me for a scan tomorrow morning they are worried in case of left over pregnancy tissue but I've had no bleeding or a possible new pregnancy has  this happened to anyone? I did a clear blue digital that said 1-2 weeks could this be wrong though? 
I also had another blood taken his morning... Has anyone had a similar experience? I am really worried about tomorrow xxx