When can we start TTC??

Had medical management 10 days ago (I had a MMC at 10 weeks, baby measured 7 to 8). Bleeding has now pretty much stopped. At the hospital they told me we can TTC again once the bleeding stops. However they also said if hpt is still positive after 3 weeks to call them to check for retained products. Tests are slowly fading....this one was first morning wee today. How much longer should I wait? I want to get going and don't want to miss ovulation!