You need to do some investigating and get back to us with more info. Does the toilet flush correctly, how about the water at all other faucets and toilets?
Time to open the tub faucet mechanism. Turn off the main, remove the handle and bezel. You should see a brass or chrome hex that can be unscrewed to remove the valve stem. Once it is out cover the opening with a towel and have a friend briefly open/close the main. Did you get pressure? If yes clean or replace your valve or cartridge.
Linear Mode
