Mentally Unstable

Sometimes I truly wonder if I’m just mentally unstable.  I do stupid things, and while I’m doing them, I know they’re stupid, but it’s like I can’t stop myself.  I don’t know.  Sometimes I know I’m being irrational, and I do irrational things anyway.  I feel like I’m crazy.  I don’t know.  I feel like I carry this constant guilt and shame and it never goes away.  It feels like there is something very wrong with me, and I don’t know what to do about it.  I don’t know how to fix it.  I wish I could, before I lose more people I care about.