How Long Does The Vaginal Bleeding Last?

Hello doctor, i had unprotected sex last month and took postinor 2, then i got my period at the normal time, but with tender breasts through out the month(May). Then this month, june, i finished my period on the 21st and had unprotected sex on the 22nd, and i took postinor 2. But i started spoting/vagina bleeding on the 28th. I knw vaginal bleeding is one of the effects of postinor 2, I m just worried. Then, for how long does the bleeding last?