For the past few days i've been waking up with a dry mouth and a sore throat that goes away once i get a drink. i don't think i sleep with my mouth open. what could it be?

Mouth breathing/meds: My first thought would be mouth breathing since that is common & would easily explain the issue. There are a few medications that can produce a dry mouth, but you should be able to tie this with the start of that med. A simple maneuver can eliminate the mouth breathing issue. You can fine a mouth closing strap to keep the mouth closed at night.