Try not to worry about the weight too much. Lots of us here have put on weight, as the symptoms make you too tired to exercise, and make you depressed and unable to do much else that is fun but still able to eat.

I also feel that my brain is less able to tolerate being low on blood sugar, so if I get hungry I am completely unable to function. So I have to eat whenever I get a bit hungry, whereas before it didn't bother me and I would keep going without food for longer. It's good to eat healthily (esp lots of fruit and veg) but there's no point stressing about the amounts.

The health of your brain is much more important than your weight so give yourself a break for a while. Once you reach a certain stage of recovery when you are able to exercise without ill-effects this exercise is actually really good for your brain, so you will be able to do a lot of it and this will handily bring your weight back down again.

If you haven't reached that point yet then be kind to yourself and try not to worry about it. You are suffering from a serious health problem and eating is one of the few comforts left to you, so not looking your best for a while is ok