First thing is not to beat yourself up about this, you're doing amazingly well already.
I'd suggest starting by keeping it simple.
Maybe a couple of nights of "things on toast" - scrambled egg, cheese, beans etc. .
Tubs of fresh soups with rolls/bread.
Sausage sandwiches and veg sticks.
Omelettes with beans (new potatoes if you can face it).
Pasta with a jar of sauce/pot of fresh sauce and a pile of cheese (or halloumi fried off in a pan).
Keep bags of mixed veg in the freezer that can be thrown in a pan or the microwave to supplement.
Then once you're in a better routine you can start thinking about more adventurous stuff/batch cooking etc.
Make bolognese using fresh mince, big handful of veg chucked in a blender so it's small, and then a jar of sauce - would be ready in 20 mins or so.