chemical pregnancy?

Donna
So for 3 days running I had 3 positive pregnancy tests. However yesterday I started bleeding and it looked like it my period. I phoned 111 and they said it's possible that I could still be pregnant but it could be a chemical pregnancy..
I honestly don't know how to feel as it's taken so long to fall pregnant.. 
How long should I leave it before taking another pregnancy test?? So I  know if it's pregnancy or chemical x