I am truly sorry for all the health problems you're dealing with. I know what you mean by self-pity--we do become experts at it! I'm no different unfortunately. I'm very busy, about to graduate and dealing with depression.
First of all, give yourself credit for the positive changes. If you meditate with the serenity prayer in mind, I think you'll be just fine because you seem like a strong, mature person.
Keep up the good work and thanks for posting--it's giving me strength today.