Struggling to model Christ's patience with my kids

I lost my temper with my son yesterday over spilled milk. Actually spilled milk. I yelled at him and now I feel terrible because he was already upset and I just made it worse. I pray about being a patient father but I keep failing. How do other dads handle staying calm when they're frustrated? I want my kids to see Jesus in how I treat them but instead they're seeing me be a jerk.