Can someone please help me out?

So Ive had a light brown secretion from my vagina. I didnt know what its from so i looked it up and the internet says its either from a miscarriage, you could be pregnant, or HPV. Ive only been with one person my entire life and im engaged to him and he was a virgin also. We've been together since we were younger. So I dont think its HPV. But I did have unprotected sex with him about a month ago but I started my period about 3 days after. And a few days ago a started have a light brownish vaginal secretion. It doesnt hurt, and its not itchy or anything like that.. What do you think this could be from??