When to test?

My husband and I have been trying for the last few months with no luck. My next period is supposed to be here on Tuesday. Last month I was a week late. I tested today and it said negative. With my first I had a strong positive 4 days before my missed period. Should I wait and test again or should I accept the negative and expect my period on Tuesday? Also I know what day I ovulated on as I have been testing, but I'm still getting faint positives for ovulating even though it's been way over a week since I ovulated. What does that mean?