Weird discharge?

Rose

My period is pretty normal, every 25 days or so. In between periods I get discharge, but it’s really light and usually yellowish colored.

I’m supposed to get my period this Friday (in two days). Today I had a bunch of really thick, white discharge in my underwear, almost three times the amount there normally is.

There’s no chance I’m pregnant or have an std, is there anything else it could be or is it just regular discharge?

Sorry if the answer is really obvious, I’m not very well informed about this stuff and google didn’t tell me anything.