My left arms feels cold and numb, and my feet feel pretty cold. Anyone know why?

You have either been sleeping on it, near air conditioning (happens to me) or there is something that could be seriously wrong. I would wait a day, if it doesn't go away, then go see a doctor.

Yours sounds like it maybe a circulation issue. Try googling symptoms of a circulation issue and see a doctor if it doesn't get better.

the er would know why, i suggest you go there, it could be your heart

Sounds like polyneuropathy. Are you diabetic? Have you had recent blood work done to be sure? You should ask your doctor to do blood work and get a nerve conductivity test.