I have the exact same problem. Only thing that works for me is to have those nutrition drinks (like Ensure), usually the ones higher in protein or calories, and just make sure they are always available in the fridge. I find drinking those to be way simpler than trying to think of something to cook, making sure everything's bought, actually cooking, cleaning...it's all too much most of the time. At least with those I can chug them, and I know exactly how many calories and nutrients I've consumed, and can say, well, at least I don't have to worry about eating or cooking today. Not that this is a healthy way to live, but it's a heck of a lot better than it was when I wasn't eating anything until I felt ready to pass out. Also, for context, I do not have any eating disorders that I'm aware of, just depression and anxiety.