I myself have MS, Fibro, Degeneritive disc disease in cervical and lumbar spine, Hypoglcemia, Hassimoto(or however you spell it, basically Hypothyroid disease), with a nodule on my thyroid, poor eyesight that cannot be corrected thanks to my MS.
When you have a laundry list of stuff that is wrong with you, you tend to focus on yourself so much that it starts to consume you. The best thing I did for myself is to go and see a therapist. You would not believe how much better you would start to feel. My therapist has worked with me to take my mind off all the crap that's wrong with me and to focus on the positive things in my life. My kids, my DH, the fact that I do wake up breathing everyday, stuff like that. I would highly suggest a therapist to anyone with a laundry list of illnesses and problems it really works wonders to be able to talk out how mad you are that you have all of this, and there's nothing you can do about it. Give it a shot.
I really do know how you feel. Life isn't fair to us sometimes, it tests our strengths and pulls every bit of energy out of us. But some how we manage to go on. Keep on going, I hope you find some relief.