Miscarriage?

I took a test last week and it was positive. I went in for an ultrasound in a clinic and they said they couldn’t see anything and gave me another pregnancy test and it was negative. I got home and sure enough after taking 2 o tests it was negative! The woman told me that I might be really early or it was a false positive. I have two kids and I know what it feels like to be pregnant so my question is ... what happens next? If I did miscarry will my period start? If so, when? Should I make an appointment with gyno? I’m at loss of what to do now?