Ttc after miscarriage Feb 19

I miscarried Feb 19 soon as my levels went down to 0 I’ve been ttc again since March 4 , we do the deed once a week , my OB did say if my cycle doesn’t come on by end of this month I might be pregnant but I have been testing every week their all negative , still no cycle since miscarriage , any thoughts ? Did anyone conceive without getting a period first .. I’m getting nervous because still no positive .. it’s been a month since my levels went down , do I have a good chance of conceiving right after