I am taking Mounjaro so my comment isn't an attempt to disparage it. I also think in time it will be available to help maintain a healthy weight rather than having to wait to be an unhealthy weight before getting support.
However the rapid weight loss you have achieved is effectively starvation:
"I've literally not been able to eat.". A fair chunk of the mass you have lost with this rapid weightloss will be muscle mass (I think you can expect muscle loss to be about 40%).
As muscle is more metabolically active than fat and you use more calories maintaining it (and of course you are lighter overall) you will of course need less calories each day to avoid gaining weight.
If you regain weight (not through a deliberate attempt to build muscle with diet and weight traing but your usual common or garden eating type) then that will be pretty much exclusively fat.
If you regain your weight (let's say you were 9st5) and you go back to 9st 5 you will have less muscle and more fat. Because of that if you eat the same amount of calories that maintained your weight before e.g. you eat 1800 calories (or whatever) instead of maintaining 9st5 you will get heavier for this same amount of calories.
TLDR: Using Mounjaro to starve yourself burns muscle that is needed for strength and metabolism. Weight should be lost at a healthy pace with efforts to maintain muscle mass as otherwise maintaining weight after Mounjaro will be even more difficult than it was before.