Welcome to Android Central! Was this a system update pushed over-the-air, or did you download it manually from some website?
Did the Play Store icon disappear from the App Drawer, or only from the Homescreen? If there's a Google folder in the App Drawer, make sure you look in there. Or look in the App Manager -- is the Play Store still there?
Wiping the cache partition can sometimes help with various issues after a system update:
https://support.t-mobile.com/docs/DOC-35597