Yelling at kids

I love my 2 children (3 year old son, 1 year old daughter) and love being their mother. Lately I have noticed thoughts of “Why is this so hard” and “I’m not sure I am cut out to do this job” and “I just need some alone time”. It is often when the kids are whining and I am trying to get something done around the house or cook a meal. I have a hard time remaining calm while dealing with the children and trying to complete the task I am working on. I have done some models, and I am having a hard time finding a thought that results in the calm mother I hope to be. Also, can your intentional feeling and result be the same? Any advice would be appreciated.
Unintentional Model:
C: Children whining and crying
T: Why is this so hard, I can’t do this
F: Frustrated, Stressed, Overwhelmed
A: Yell at kids
R: More whining and crying from kids, I am more stressed
Intentional Model:
C: Children whining and crying
T: ???
F: Calm and in control
A: Connect with kids and respond in a calm matter
R: Calm Mama

Thank you!