I'm sorry, that happened to me a few years ago and it really sucks. Many of the things that ended up being helpful for me are things people already mentioned (unhealthy food is much better than no food, takeout, multivitamins). I had a subscription of Soylent sent to my apartment every month, and that did a lot for me. I'd feel pretty bad if I had nothing but Soylent in a day, but if I had two or three of them, that cut the calories I needed to get from "real food" roughly in half, which made it a lot more attainable. And due to it being mild-tasting and easy to chug down, I could handle it even when sensory issues were making most food too hard to eat. Other meal replacement shakes could probably play a similar role.
Spironolactone can complicate things, if you happen to be on that, because it messes with your sodium levels. Sometimes when I managed to find some energy and eat "healthy" for a day or two, I would start feeling really bad, I think because I wasn't getting enough salt. And then I would fall right back into the rut I was in before. I didn't really solve that until I was doing generally a fair amount better, but the solution I ended up going with was: When I felt physically bad in a way that was hard to identify, I would put a bit of table salt on my tongue. If it tasted really good, I would have a salty snack and that would usually improve things.
This one might not be very actionable, but something that helped me a lot was living with another person and sharing meals with them. When I didn't have the energy to make things, they could do so, and it was a lot easier for me to find energy for cooking when it wasn't just for me.
