Since you are getting water at the sprayer, it is likely that you have a clog in the diverter or the faucet. If you know the manufacturer of the faucet, you may be able to find troubleshooting and repair information on the manufacturer's website. If you do not know the manufacturer of your faucet, you may be able to find repair information by conducting a web search based on the type of faucet that you have. If you are able to disassemble the faucet, you may be able to find a clog in the diverter or another part of the faucet. Be sure that you shut off the water supply to the faucet before beginning any repair work.
If you need to replace the faucet, this Manage My Life article provides basic information on faucet replacement: