Left beef roast in crock pot..apparently it was not cooking?

At ab 9 or 10 last night I put a roast in the crock pot...the potatoes. .carrots onions and celery..anyway...the knob on it is missing and I turned it to what I thought was the low setting. I got a phone call not too long ago and its ab 440a that I went to check on it and noticed I didn't smell anything on the way to the kitchen and saw that the pot was not on... I turned the thing till I felt it get warm at the bottom... should I just throw it away and by another one? I wanted to try and make a roast but obviously I failed.