Ttc #1 please help. need input.?

My fiance and I have been trying to conveive since april. If I started my period on may 3rd and it ended on the 7th and I ovulated from thw 16th to the 21st would it be to early to take a hpt and it come back possitive,,?? I had a spot of blood about 5 days ago when I went to rentroom about the size of a pencil eracer with some cramping. Now I should be having my period but I have no period symptoms or pregnancy symptoms. Does this mean I'm not pregnant. Please help.....