Hi
I'm not sure if pre-diabetes and insulin resistance are the same thing. But I seem to be having a lot of troubles with very low blood sugar too.
I am getting nowhere with the doc, so have self imposed the following exclusion diet:
Wheat - any kind, even low GI
Dairy - As it can stress your digestive system anyways
Caffine - Plays havoc with adrenals & blood sugar regulation. I love my coffee, so am having de-caff (some diets will tell you not to, but I can't help it).
Sugar of any kind!! I occasionally have a little honey. And to stop myself tipping over the insanity edge I allow myself 2 sqs of 85% cocoa dark chocolate each day - or my sweet tooth goes nuts.
You need to start checking ingredients on packets as you'd be surprised that sugar is included in most things - cereals, soups, sauces, you name it - its in there!
Oh - and no alcohol!

This one I found hard, as a self confessed party girl, I have had to do a complete 360 turn-around in my lifestyle.
I don't have any processed food - and have started cooking everything from scratch as much as possible.
Loads of green vegi's are great - but go easy on starchy ones as they get converted to sugars too quick - so potatoes, sweetcorn, should be something you have only occasionally. (although, if you eat them with protein it brings down the overall GI).
As someone who used to run or spin everyday and had to stop, I have been really worried about my fitness and weight - but I have taken up yoga instead, and try and do a little every other day. It works on the whole body and is very healing - great for stress and anxiety too - and is extremely good for strengthaning and toning - plus, you leave the room with a bounce in your step, so I'd recommend it to anyone. It might not be for you, but give it a try.
I know the diet stuff and the problems are daunting, but give it a go, because although it's a pain I have found that it is actually worth it to feel better! It took until my 4-5 week of eating this way to start to feel better.
Let me know how you get on, best of luck and feel better. xxx