How do you manage a cheerful disposition??

I have become SO mean and rude and impatient. I've found myself coming that person who is always yelling and nagging about something stupid. My poor neighbors have to hear me annoyingly yelling at my dogs constantly and sometimes even my sweet boyfriend. I don't want to be so mean and impatient. Like I cannot describe how irrationally mean I have become. It makes me worry I'm going to be an awful mother. I've never been like this before. I'm always fairly calm, cool, and collected. I don't get heated easily. I'm super patient.