2001 Subaru Outback Engine sounds AWFUL suddenly

[Jagrif425]

During holiday shopping, my 2001 Subaru Outback/Legacy had been turned off for about 15 minutes . I cranked it back up and it started fine. Two minutes down the road at a stoplight, a terrible grinding/chattering sound started coming from under the front of the car. I pulled into a gas station not too far down the road, turned the car off (it was still making the noise) and popped the hood. I'm definitely not a car expert but it felt like the alternator was excessively hot, and was the general area the sound seemed to be coming from. The sound came back as soon as I restarted the car. I turned it off again and kept the hood open to let it cool for a little while before driving it about 10 miles home. It seemed to me that it was sounding a little better since it had cooled off.
The next day I started up the car in the morning to take it to the shop, and the noise was still there. It sounds like metal scraping, but there's a rhythm to it that kind of goes along with the idle. I drove it to the auto repair just for them to tell me that it was "making all kinds of noise", and suggested I drive it to the Subaru dealer (about 20 miles away). I should have called first, but I drove it out there and the dearlership had closed early the day.
Trying to get back home, I noticed the accelerator was slow to speed up (until about 45 mph at which speed it seemed that the noise had decreased significantly and accelerator started acting normal).
I started it up this morning to try to get it back to the Subaru dealer. The sound (like a diesel engine/grinding metal - LOUD) was there, accompanied with a slight squeal at the beginning that ceased about 3 seconds after start up. I put it in drive and the accelerator was again very slow to catch, and at the same time caught wind of a strong odor, almost like a playdough-y smell (could be burning plastic?). I had the windows open so I could listen so I'm not sure where the smell came from but I quickly backed it into the driveway, parked and shut it off.

Does anyone know what could be going on? Possibly a too tight belt? I have holiday traveling planned and am kind of nervous that I totaled my car by driving it after I first noticed the sound.