Why is my washer making a loud noise on spin cycle?

I was washing some linens the other day with the option on bulky. The washer was no where full as it was a comforter and 3 small towels. On the spin cycle the machine started to really shake and then sounded like someone was fighting on the inside of it with loud pounding. it completed the cycle but then the linens were still very damp. I tried running the Spin and Drain cycle but the machine made a very loud, weird grinding noise and would not perform the fast spin just a slow spin motion instead. In the middle of that the machine would stop doing anything ans the spin indicator light would just blink. Can someone help me figure what the problem may be?