Ah, it's rough, I know. Is it helpful to know that biologically we're not designed to self-settle or sleep alone as infants? Sometimes we assume there's something wrong with our babies - or us! - when they are actually behaving like normal babies.
Right now, what works? Wearing him in the HAB, feeding, yes? Anything else? My honest advice is to just do what works and what is going to be easiest for you right now. Don't worry about the longer term - it'll sort itself out with time. Right now he needs to sleep and you need some rest too, so whatever is easiest may help.