I've been a type 1 diabetic since 1975. Since diagnosis, I have done 23 Alpine seasons and now have the Woodcraft School Bushcraft Instructor's qualification. Ultimately, the easiest way to manage your diabetes when out in the woods or wilds is to monitor your blood sugar levels more closely. I don't know what regime you're on for this but increasing the number of tests you do each day to include ones about two hours after eating is extremely useful.
It is also very important to have a back up with you. Glucogel has been mentioned (vile stuff) and Mars bars, both of which will do the job to an extreme degree. I've found that having a tube of honey is preferable: it tastes a whole load better and, being a natural substance, is 'better' for you. Although full of sugars, it does not produce that soaring blood sugar high like other, more synthetically produced food stuffs. The other secret is to stop what you're doing and wait until things return to a more normal level. The temptation to scoff some food and just carry on is very high but can, of course, carry certain safety issues with it if you are using cutting tools.
Carrying these extras does fly in the face of your desire to follow the survival ideal but you MUST be realistic: you are diabetic and you owe it to yourself - and to any others with you - to be responsible. Your survival outing is only a game, after all. If you are competent and confident with the skills required to survive, then, should the poop hit the fan, you'll be OK and you'll have to juggle your diabetes in a much, much harsher environment.
I don't wish to sound bossy or parental over this but years of experience following these activities with a rather more 'brittle' form of the condition has taught me some very, very useful lessons, tips and tricks over the years. Your GP will certainly help but do remember that he/she will be giving you advice without any experience of living with the condition, unless he/she suffers similarly. If I can be of any further help, please do email or p.m. me.