Hey Lisa,
First off, I love the avatar picture. As for whether you're diabetic or not, well, we can't exactly diagnose online, but don't jump straight into a diet you know nothing about just yet. Read first, learn, and discover what is right for *you*. You've tried a LOT of diets, and the thing with low carb/high fat is, well... It's pretty much for life, if you want to keep control of your bloodsugars. Whether you lose weight or not is not the issue (though people usually do on low carb), the important thing is getting control of your bloodsugars. And you need to really commit to this. Best way to do that is to read up, find out what you actually like to eat, and that'll help you stick with it. (There are keto-mugcakes, and bacon is my bestest buddy in the world.) I mean, you can make adjustments to your diet, of course... But rushing headlong into it might just be extra stressful and people tend to make mistakes at first when they rush things. (I know I did.

). If you want to learn about low carb or keto, check dietdoctor.com, and remember a couple of things.
First, a meter is a wonderful tool, IF you're pre-diabetic or actually diabetic. Check before a meal and 2 hours after, and if the reading went up more than 2 mmol/l, the meal was carbier than your body could handle. (T2 is the inability to process carbs out of our bodies again effectively, after all.)
Secondly, fat is your friend. Like others stated, forget everything you think you know. There's been a lot of research recently that just disproved everything we've been taught.
Thirdly, white or brown carbs, doesn't matter. The "glycemic index" is an interesting concept, but in the end, a carb is, in most cases, a carb. So if you do decide to go low carb, rice, bread, pasta, oats, corn, cereal and the like are mostly off the table, even if it is the brown variety. Loads of fruits too, as there's a lot of fructose in there... Though berries (especially with cream of full fat greek yoghurt) are fine in moderation.
Fourth, and this one's REALLY important: You're not alone in this, if you are pre-diabetic or diabetic. You can ask anything here, and usually someone'll have an answer. More often than not there'll be loads of answers and you can decide which resonate with you.
You'll be okay. And you're not alone.
Jo