I Think I have bipolar/anger management

Hey guys, I think I might be bipolar, I've noticed this for a while but never really looked into it but basically I've consider myself to have two versions, the first version, I'm nice, caring person who tries to be as nice as possible and treat people with respect and be polite, but my other version I just don't give a sh** I'm constantly angry, and don't care about anyone or anything and take pride in hurting peoples feelings. I've always thought that's just because I have bad anger problems, but how can I go from trying to be nice and treat people with respect to not giving a sh** and wanted to beat the hell out of people.