What Causes Spotting After 2 Days Of Menstruation?

Hi im almost 21 me and my partner are trying to conceive for a few months now so i started spotting last friday and saturday then came on my period on subday i had a normal period for 6 days then 2 days later i start lightly spotting again, headache anf stomach feels like i will start period again. Whats going on?? Confused and scared somethings wrong