Cycle day 33 after mc, no period and no bfp

I had a very early miscarriage (just under five weeks) and am 33 days since. I have no pms, don't feel pregnant, and first response tests show nothing. I've never had an irregular period before and its freaking me out! How long should I wait till in see a doctor? I've been having sex as my friend who is a midwife said it was so early that normally I wouldn't have known I was so there was no harm. So confused.