What to do if I often wake up with my hand and arm totally numb. Do I have poor circulation?

Carpal T Syndrome is. More likely your dx, as its a very common problem. Use a wrist brace throughout the day and night would help considerably in improving your symptoms. Its recommended for night time mostly, but i advise it through the day as well, as one can do most activities with it, except some. If not improving consult your pcp or an orthopod.
Numb. this is not related to poor circulation, and more likely is representative of nerve compression. Based on the area affected the problem may be coming from the neck area. I would recommend evaluation by neurologist.