1995 Mercury

I have a 1995 Mercury tracer 103,000 miles bought it about three months ago. Today when I was driving home the car began accelerating by itself I tried to press the accelerator in case it was stuck but it kept going faster so I had to keep the brake pressed until I got home. Luckily I was only two blocks from home. I also tried to lift up the accelerator with my foot but I couldn't. I turned it off and then tried turning it back on to see if was still accelerating it was I just had t o turn it off. Any ideas what this could be?