Why can't I be angry if I want

So I'm usually very funny and happy at work and today was having a bad day I've been very depressed my job is been horrible my ex is in town to stressing me out my cat just had surgery so I wasn't feeling good and you know in the beginning of the day somebody even said you know you don't look yourself and I said I'm just having you know I just don't feel good so then I went to help them with something and something they said must have annoyed me or something they didn't oide me and they're like well you sound really nasty and I said I'm not allowed to have a bad day too I don't understand you know people take stuff personally I have the worst bosses sometimes and I let it go I say one thing and everybody gets mad at me so my day is over and all I kept thinking is that I feel guilty for having a bad day so I think I'm going to start becoming a voluntary mute and I'm not going to talk to anybody so I don't hurt anybody it's a horrible feeling because I'm a very social person and these mood swings I've been having I really starting to affect my relationships