Mazda 6 making high pitch whine?

I started to notice a high pitch whining noise when driving my car, especially when coming to a stop. While I was driving it today there was a bit of a "clanking" noise, I thought I had driven over something. After that, the noise seemed to get worse. When I got home and parked the car, there was this constant loud whining/whistling coming from the hood! When I opened up the hood the noise seemed to be coming from under the engine somewhere although I cant be sure it was hard to pinpoint...help!!!