The Flow of Flo - what's "normal"?

By the 2nd day of my period, especially in the morning, I have what I would say is an excessive amount of flo. Feels like when I stand up after a bit of sitting that it is going to gush out like a kool-aid waterfall. It quickly lessens by the next day but I'm just wondering if I've got something weird going on like endo? I'm always very regular and don't have excessive cramping. The first two days this month I didn't even take any Advil.