I used to not give a fuck and I miss it.
Why do you want to no longer give a fuck?
Because I constantly do now and I feel like I should stop.
While sometimes it's fine to just shirk your responsibilities if you're overwhelmed, it shouldn't be happening every single time. You will just be seen as careless and aloof, perhaps to the point of others not wanting to be around you.
I understand, but I wanna do it.
Sometimes caring about things can feel like an annoying or a waste of time, but you should still try. Have you considered taking some time off to yourself so you can recharge and refocus your outlook? It sounds like you might be tired and stressed out.