When to test again .. ?

I got a faint positive pregnancy test this morning on a wondfo!! I am not telling my husband until I know it's for sure . When should I test again ? I really want to try a FRER tomorrow morning with FMU .. Is that too soon ? Should I wait till Friday or Saturday . AF due Sunday.  Sunday is also our 1 year wedding anniversary !! Ahh what an awesome gift for him if that test was truly right