All of us with chronic conditions have to arm ourselves with knowledge.  The hard part is timing to implement your emergency plan.  Once you have that you can stock up with a good buffer to achieve it.  That doesn't mean run out and buy a pig or two, not immediately anyway.  Now you learn.  

For example, the animals most frequently used in natural drugs are pigs, sheep, and surprisingly horses.  They're basically the closest to humans in many chemical factors.  The rest is chemistry, development techniques, and trail and error.  A couple weeks is a good sized window.  Someone with say diabetes and on insulin has one very narrow window.  

In your planning, don't overlook diet and exercise.  Things like having to lose weight afterwards, plan on keeping some weight on you.  Contrary to popular survival thinking, having a few pounds on you when you have to go a week at a time without food is a good idea.  I personally have lost 50 lbs since my all time high but because I have Crohn's, I'll never go down to my Army weight unless I have no choice.  I'd really not rather do the movie "Shooter" homemade sugar IV thing unless I have to.

Now to encourage you, once you gain the knowledge, which this thread is a good start, you will find its probably not going to be easy but not insurmountable.  

Tj