Pregnancy

I was on the depo shot for 4yrs last shot was in September 2014 Iast time i had a period was in December 2014 I want to have a baby so I started taking fertilaid in may 2015 got my first period June 1st 2015 and it was light and lasted for 4 days I been checking to see if I ovulate been negative for 2 mths but 6 to 8 days after my period stopped I spotted a couple of times not sure what is going on I took 2 pregnancy test all negative can someone please help