Okay, here goes!
1. Your fasting level means nothing. I know nothing of any other test but the gtt that will show hypoglycemia. Furthermore, it's never really the level of the drop but how fast, always remember that. You could have a fasting of 85, take the sugar, watch it rise to 105, and then drop to 65. This is normal, for diabetes. Not for hypoglycemia. Once that happens the body and brain cannot keep up with the speed of the drop and you get your symptoms.
2. If it was low when you had the fasting level, all it would show is you have fasting hypoglycemia, where you can eat anything. But you don't.
3. The good thing is you're seeing that eating directly effects how you feel and from what you said I pretty much gaurantee you have the saw-tooth curve. That's what it means if you're feeling a drop within 1-2 hours after eating. I used to get them within 1.
4. The unfortunate thing is the healing process takes a lot of time. Three weeks is nothing, it's like a decade in an eon. Well, not that extreme. The good thing is you see you can feel better on the diet, which pretty much verifies you have hypoglycemia so don't worry about anything. Remember, never worry about a symptom unless it persists almost every day for at least two weeks and it has nothing to do with your eating.
5. Another verification is that you said you can eat berries later in the day. That's because your body at that time has built up enough energy to counteract any possible drops. Classic hypoglycemia.
6. Not tolerating grains is another one, and many people can't eat them at first, regardless of what different diets say. We'll worry about this much later, whenever I figure how to add them back in myself!
7. Another marker of the hypoglycemia is that if breakfast is not right you have a bad day. Classic.
8. Remember, you're doing better. You may not be fully there yet, but you can tell there's a difference, always remember that. That will keep your mind at ease if you start to obsess. Your symptoms don't sound too extreme, so I think you'll be fine. One girl here once, who i'm pretty sure had hypoglycemia, was going crazy. As far as I know she tried the high-carb diet after not being able to deal with the low-carb and she disappeared a few months ago. I'm not sure what happened to her. Anyway, I bring her up because she went crazy about other diseases, obsessed about them nearly every day and got tested for everything under the sun.
9. I myself thought about the monitor, but it seems superfluous to me. I mean, you can tell when you eat something bad because you feel like crap, all the monitor will do is show you what the level is. Not going to help any because you can't do anything about it at that time, you can just say yep, uh huh, it be low, and then sit there. Considering that good ones cost upwards of 80 dollars, I don't think it's worth it or necessary.
10. The main problem now is that you can't really do anything about the drops. You should notice that you get a little physical sensation before anything else comes on, so you could always try having a few nuts or some fat or meat right before it gets worse. That can help, just don't make a big habit of it, remember we're trying to retrain the pancreas, not allow it to continue what it's doing. It's not like eating a bit more would do that, but you want your body to say okay, I have to cut it out because he's not giving me anything.
11. A further note, i've decided to add back in a multi-vitamin to my diet, but only in very, very small amounts, like 1/3 of a tablet. I found that in one day I noticed a change, most likely because my diet is low in b vitamins. You may want to look into one, and add it to the morning meal. Make sure you read the label if you do and check to see if there is anything at all in it. The best vitamins can only be bought at organic health food stores and will say stuff on the label like "contains no starch, sugar, grain..." that's what you want. I'm going to research into foods that carry enough b vitamins. That's the only problem with the diet, I researched and this seems to be the only way to get them without going all grain crazy. It might help out your vertigo and everything if you try it. Just make sure not to take what the label says, it's always unnecessary. You don't need 1,236% of vitamin b6 every day. I forget what mine says for a tablet, something like 600%, so 1/3 of that is plenty.