Hi there. Well, that is definitely what they call crash dieting! Sudden weight loss caused by drastic measures rarely lasts. You're finding that out. I certainly won't call you stupid for getting into that. Lots of people do it. I've tried it too myself. Once my sister and I when we were young read that you can eat whatever you want before 9 am. So, we'd get up and pork out. Then you eat nothing but a piece of fruit at 6 pm and water throughout the day. Oh my gosh, crazy, right? It's funny when I think about it now that we did that for a couple of weeks.
Anyway, I can relate to body image worries. Wanting to lose weight, stressing over every bite, trying to control it, etc. You've structured so much effort around it that it has taken on a life of its own. Remember, we eat for fuel. You only need enough fuel to fill your tank. Eat small amounts, stop eating in the evening and don't eat at night-- don't eat again until morning when you have a light but healthy breakfast. Eat lean. Lots of ways to eat for health. If you want to get something like fitness pal or some other app, they can be a little eye opening in terms of what we should be eating. 600 calories a day is not realistic, you need more.
You know all this. And are asking about anxiety. I just think you DO have anxiety and it manifests in the area of eating for you. You don't have an eating disorder per se but you are not having a healthy relationship with food and your body image.
Feeling suicidal is a whole other ball game though. That is not just body image and eating anxiety--- but mental health that should be worked on with a professional. Would your parents allow you to see a therapist? I think this would be so important for you. You go to an extreme emotional state over your eating.
Have you ever heard of sensory integration disorder? My son has had some of what you describe--- overwhelmed in crowds and eating issues (had to see an eating specialist) and he has sensory issues.
So, I think what is going on is a manifestation of the anxiety rather than the dieting specifically giving you anxiety. Make sense? It's a little like which came first, the chicken or the egg. They are definitely totally interrelated. But the anxiety doesn't sound new. Just exaggerated now more than before.
Obviously we're not qualified to diagnose you, and nobody can diagnose someone from afar, but there are a couple of things you say here that raises one possible issue, and that's a blood sugar problem. You say when you were young you got what you call panic attacks before eating. Maybe so. This could be just another case of someone with body image problems focusing on it and going about fixing it the wrong way -- instead of eating sensibly and exercising more doing radical things that eventually leave you in a form of starvation that eventually manifests in metabolism problems and all the symptoms of not getting enough nutrients because you're not eating a variety of foods and not eating the right proportions of them. When you first starve yourself, and people who fast report this, you can get a lot of energy. Until you start to starve, and then you get all kinds of symptoms. Different people do have different metabolism, and so have different needs for food. But it's at least a possibility that you weren't getting anxiety attacks but were instead feeling the effects of low blood sugar after a period of not eating -- between meals. Your ability to make and utilize insulin should at least be looked at based on what you're saying here. Until you rule out all possible physiological causes for what ails you, you really can't say it's a mental disorder. Lots of nutrient deficiencies and physiological problems can create the same symptoms as anxiety. It can cause anxiety. Things like thyroid, which is intimately related to your adrenal functions. You were right, your Mom needed to take you to the doc. But you're 19 now and you can take yourself to the docs and see what turns up before concluding you have a mental illness. If it does turn out the docs can't find anything wrong, that's when you have to start deciding it's a mental problem and treating it as such. In the meantime, do some research on the Mediterranean Diet -- it's just the real basic what we've always been told to do kind of lifetime eating style. It has enough of everything to keep you healthy until you find a way to battle this. By the way, lots of people don't do well with caffeine -- I've never liked it or reacted well to it, even long before I developed my anxiety problem. I'm the only person I know who hates coffee and cola. Now, chocolate and green tea don't bother me, but they're more balanced with antioxidants. All the best.