What could be causing my hands and fingers to always be cold?

Many things: Problems like these can only be correctly handled by your doctor in person. He/she needs to listen to you, perform an examination and possibly run labs or other tests. That's the only way he/she can find out what's going on and what to do about it.

Cold hands & fingers: This likely has to do with circulation in your hands. Here is an excellent article about cold hands by the american society for surgery of the hand: http://www.Assh.Org/public/handconditions/pages/cold-hand.Aspx.