You may have better success in a smaller caloric deficit. 1000-1200 calories a day is very few and that’s a very fast pace of weight loss. Try removing 500 calories or 10% of your calories. Progress will be slower, but you may feel much better.

Also, as a sibling comment alluded to, when you have fewer calories to eat, the micronutrients in the few foods you do eat matter that much more. The nutritional quality of food you need to stay healthy increases greatly when in a caloric deficit. Fruits and veggies are great for helping that, and multivitamins are cheap insurance policies to make sure you aren’t deficient in anything important, IMO. YMMV. Best of luck with your goals!

> my body suffers immensely

Does the same thing happen if you slowly wean yourself down? Are you cutting out essential nutrients that your body needs to function properly rather than the unnecessary carbs/junk? The reason I'm asking these things is that people I know who have reduced their caloric intake usually report feeling better, not worse.

That reaction may have to do with too much cutting, as another commenter alluded to, but it may also have to do with the types of nutrients you are missing when cutting.

Calories are not created equal. They are equal in physics sense, but your body is not a "bomb calorimeter" (device to measure caloric content of whatever). So maybe instead of cutting your calories in half, you cut less and replace carb calories with fat calories or protein calories. Or maybe you can even cut to 1000-1200 by replacing your calorie source with something else. For some weird reason carrots with butter work very well for me and I love the taste :-)

That sounds like a convenient excuse not to change

This is not a moral issue.