Unusual Period?

ok so my cycle is usually 35 days apart, it's been like this for years. Generally my period lasts for 7 days, the first 3-4 days my period is super heavy. This month, the last day of my period was the 5th, and 3 days ago, I had brown discharge. The next day, after I masturbated I noticed I was bleeding, so I figured I started my period early. But the last few days I haven't had cramps or anything, just really light bleeding. The only changes recently is that I started taking evening primrose oil and a stronger biotin pill. wtf is going on?