To test or not to test?

My period according to glow was do July 6th. Sometimes it's off by a few days though. I havnt had any of my "normal" period signs other than slight achy breasys, and today I was nauseous and a little crampy. Earlier this week I almost blacked out (many people have said its a common pregnancy sign). I don't want to waste money on test, just for a negative and a period a day later. Should I wait or go ahead and test? Opinions?