Yes it could be too early!!! Test again tomorrow and Good Luck!!! I am still waiting for AF 1 day late - FF says I might like to consider testing on 13th May LIKE WAHTTTTTTT?????!
Good luck, I am in similar situation, was due on yesterday, no af yet, but have got symptoms, crampy, bad wind, and the strops! So im not holding my breath. Oh well heres to next month.