Wondering if this is the right choice

I am a mid-40s woman (pre-menopausal) and I think this could be either a good choice for me or a terrible one. I did 14:10 for about three months, and on the whole, I didn't gain any weight, which was about as ambitious as I felt at the time. Now I want to try 5:2, but I am not sure it's right for me.\* I have not been "diagnosed" with low blood sugar, exactly, and I have never been called pre-diabetic, but all my life I have known that I may get dizzy if I don't get a good carb after twelve or so hours. A few years ago I lost a lot of weight on Nutrisystem, but I gave it up because one morning after eating a granola "breakfast bar" that was really half candy, I almost fainted on the subway. (I may have also passed out in public for this reason, but that was a long time ago and I'm not sure why that happened.) Even when I have done a calorie restriction diet, I have to leave a couple of days mostly empty in order to get over the dizziness, headaches, difficulty concentrating, and fatigue, which will slowly go away over time if I keep at it. But at least I get something to eat then, and I can't act that way two days out of every week. Is this part of anyone else's experience? Any advice? \---- \* I tried it once around the holidays when I was feeling disgusting, but that lasted until, like, 2 pm.