Help with disciplining technique

[EngineerMumOf2]

I sometimes get really upset with my children and snap at them. I feel extremely guilty after that. For example, today, my son (age 6) woke me up when I was sleeping, and I shouted at him. I don't want to do this, instead keep my calm all the time. I felt very guilty after that. I apologised to him multiple times. He cried. It created a chaotic environment at home.
I need some help in breaking this cycle of getting upset with children -> feeling guilty -> saying sorry -> giving in to children or overcompensating -> getting stressed and tired. This is affecting the emotional health of my family and general wellbeing. I need more effective disciplining techniques, that helps me keep my cool without yelling and then feeling guilty.

Were you napping in the day?

As yelling today wasnt a discipline issue??? He was waking you up? Unless you were on the night shift last night and his other parent had told him to leave you asleep, you should be awake when a six year old is awake.

What time did your 6 year old wake you up?

I don't know if it's possible to be calm all the time

It was around 8:30; I was very tired and my DH was at home to look after kids.

Then why did your dh allow him to wake you up. Yell
At him, not the child.

Does your dh share the parenting properly? If ot was agreed he was getting up with them that day, but then let d.s. wake you up, he was being a shit partner.