How early can I take a HPT?

My next period is due the 28th of this month. I've had really early pregnancy symptoms.. my predicted ovulation day was the 13th but I think I ovulate on the 9th or earlier.. I am antsy to take a test of course but I only have one atm so I don't want to waste it . I am being impatient and should just wait till I do or do not miss my period but I was just curious! Thanks for any info..