Sally,

Depression can be very common with MS, sometimes as Chris mentioned depression can be situational or it can be due to the MS.

Depression can do the things you have mentioned and much more. Seek help from your doctor....it's time to take action so you will be ready to deal with the choices you will need to make after the testing is done.

http://www.nationalmssociety.org/spotlight-emotions.asp

Hang in there, ADs can make a difference.