Implantation bleeding?

Ka

Hey all! I’ve been off the pill since March but just started really TTC about 3 months ago. According to Glow I should have ovulated last Saturday (8/3) and be getting my period this Saturday (8/18). Today I’m having some light spotting and cramping. Could this be implantation bleeding? I tested today and it said negative. Hoping it’s not just my period coming early. Has anyone experienced this?