implantation ???

Hey ladies! 
So a week ago I finish les my first round of Clomid! Monday I noticed lighting spotting just enough to notice on my panties and had mild cramping!! Contacted my doctor who called me today and said I could have ovulated early and it could be implantation! I am going Tuesday for pogesterone check! He said it was to early for an ultrasound and testing! 
Could it be true? Can you ovulate early (within taking Clomid that early) and have implantation??