Hello Dear Sally,
I am so terribly sorry you are going through this. Yes, depression can cause many problems including anorexia (the loss of appetite), as well as trouble sleeping, increase in mood swings, lack of motivation, amongst a multitude of other symptoms. In addition, MS in itself can cause depression. I concur with what the others have said and believe you ought to try and take one of the anti-depressants that will increase your appetite as a side-effect of the medication as well.

Even if you are going through what we refer to as a "situational depression", I would recommend seeking help so that you will begin to feel better overall, and some of your MS symptoms may even be abetted as your depression lifts.
I believe we've all been in your shoes at one time or another; some more depressed than others. I wish you all the best and hope you take solice in knowing that you are not alone. There is life and laughter after being diagnosed. For some it just takes some time and extra help. Hang in there dear Sally. I shall be thinking of you, and hoping this is just a bump in the road for now.

With heartfelt thoughts,
Chris