Excessive amount of discharge?

Usually before my period starts (2-3 days into my period pill week) I get this milky white, thin, watery discharge. Yesterday and today, all day, I’ve been getting it as expected (I’m supposed to start bleeding within the next couple days,) but there’s a ridiculous amount. It’s to the point where my underwear is soaked and I think my period already started!

The smell isn’t weird or anything; it’s a normal, neutral smell. The color isn’t funny, it’s just the amount! I’ve had unprotected sex this cycle (I am on the pill) but it was fooling around and he never finished inside which kind of debunks being pregnant.

Explanation?? I feel so dumb as I’ve had my period for like 4-5 years now but I feel it’s better to ask here than to go on google and freak out about being pregnant.