Yes, sounds like you are experiencing derealization and maybe even depersonalization. You mentioned that you don't care much about the world around you as well as yourself. Dissociation makes you feel numb to prevent feelings of intense mental/emotional pain. If you truly did not care you probably wouldn't be in this mental state or even bother to write this post. You do care and realize it's an issue, that is the first step. From my experience, it's best to attack dissociation indirectly by understanding why it occurs. Try to think about what in your life is causing you to feel this way and work on that. Find someone you trust that will listen to whatever is bothering you. I would recommend seeing a therapist/psychologist to talk it out with. As for when you are dissociating from your environment, try using the 5 4 3 2 1 method but do not beat yourself up if that does not help. Getting frustrated whilst dissociating tends to make things worse.