I relate to this for sure, especially when I was first living alone. It’s natural to want to continue spending alone time where you historically have, so I wouldn’t worry too much. I would however try to optimize the space for how you want to use it. Maybe it feels empty because it is? You even said you decorate differently depending on where it’s going. Perhaps try to make your living room an extension of your bedroom. Carry the theme into that room and lean on the door being open to build cohesion. If it feels less safe, maybe try some things to make you feel enclosed. Some tall plants, over stuffed chairs, that kind of thing.
At the end of the day, being satisfied with less square footage than you have available to you isn’t a problem, it’s an asset. Good luck!