helppp

Okay ladies, this will be month two of ttc, my last period was April 26th, they usually last anywhere from 5 to 6 days nothing more. My fertile window was from may 7th thru the 13th being the ovulationday the 10th, i tried doing the deed at least every two days. I am due for AF tomorrow. When should i test? wouldn't it be too soon to test? How does this work? lol i don't wanna kill my wallet buying tests for no reson.