I relate to what you say. It's not your fault though.
Health is down to inheritance (genes/nature) and environment (nurture).
I had an 'easier' childhood than many people with similar problems to me and I often feel such a wimp. I have to remind me that strength isn't about how healthy we are, but how we deal with the health we have.
You're still here and you still post on PC, so you do have strength.
Be kind to yourself, you deserve it. YES YOU DO.
http://www.wired.com/wp-content/uplo.../10/cathug.jpg