After my shower this morning, I heard dripping water, so I turned the shower handle farther to the right to stop the dripping. But it didn't stop. I turned it to the left, but there was no water flow. I had just gotten out of the shower two minutes earlier, and now I can't turn on the faucet or shower at all! But the water keeps dripping out. If I try to plug the faucet, the dripping immediately comes out the shower head.

It is a Moen single-handled faucet, the type that looks like a teardrop.

I really need to fix this quickly, because water is being wasted, and we obviously need to be able to shower. I have never tried to repair a shower before, so please don't get too technical on me.

Thanks in advance for any help I can get.