Possible explanations for this?

How I'm feeling mentally is all over the place like for a day or a few days I'll feel one way and then feel a different way, and nothing seems to give me lasting enjoyment anymore, I mean I'm not avoiding talking to friends and family it's just that I guess I'm living in the moment and positive feelings are temporary, sometimes the only satisfaction I get that lasts is the stinging Feeling I get in my legs after I cut them, I guess I would say cutting myself is enjoyable because at times I'm totally emotionally dead and can't even get momentary satisfaction, Friday even felt unrealistic to me, like a dream of sorts where my body was on autopilot under control of my mind and my spirit was missing , perhaps watching my body.