I don't know the right answer. I feel for you, this situation must be hard.
If you suspect that this might be some sort of an eating disorder, it would be advisable to consider therapy. If you think that therapy is useless, or if you have had bad experiences, maybe write down what goes on in your mind when you start having urges to eat something that makes you sick. And then go on a walk. Walking helps to clear your mind. But our minds are tricky, they tell us to go to the store "I have to get something rewarding, after all, I was good and didn't eat junk today." Then, I don't know how, but just try to walk somewhere where there isn't any grocery stores nearby.
Breathe deep, meditate, strech, take a shower, for example... Just do something, to feel your body, and distract yourself from harming yourself.
If you fail, it isn't the end of the world, you can always try again.
Take care.
Ps. If you find healthy food tasteless, maybe try some very spicy foods instead? Ingredients like garlic, chili, ginger, turmeric, cumin, mint, cinnamon, there are some wicked recipes you can concoct, when you learn to use the spices that you favour... and sauces like sriracha, tabasco, you can add those to almost any food and pesto, that you can use on top of bread (maybe pesto is not that healthy, but still)... There are a lot of options, and easy recipes that you can try out.
And maybe it doesn't matter that much if the recipe is healthy or not? You can start by preparing those foods that you find delicious, and then, gradually move towards more healthier options. The cooking part in itself can be very rewarding, as you learn more of the ingredients that you like.
Also, eating more protein can, in some cases help control sweet tooth. If you hate regular tofu, get spiced, or add spices while preparing. Some protein shakes might also work, but I have very limited knowledge of those.