Xeljanz - How long to take effect?

Xeljanz Timeline

Hey y'all! I started taking Xeljanz about a month ago; my doctor put me 20mg a day (one in the morning, one at night). I was wondering how long Xeljanz takes to reduce UC symptoms? About two weeks in, I had 2 days where my stool was solid, but then returned to how it was before (mushy, mucus-y).

Also noticed it makes me decently drowsy (like taking a melatonin supplement) and causes my joints to ache for some reason? Mainly the area behind my knees.