we no longer have good days

i have two 4 year olds and one 5-year-old and we no longer have a good day everyday its always yelling for them fighting with everyone no listening even a little bit just constantly having to yell for them to even pretend to do what I ask or to have them stop doing whatever it is. I know parenting is supposed to be hard, but I am doing something wrong it should not be this angry and painful and just stressful