Tell me how to keep my cool?

Once again, I lost my cool at Miyoko today. Scolded her and slapped her thighs. I know I shouldn't do that but I completely lost it.

She was crying for milk but when milk was served, she played with the teat. Took it away, she cried. Give her she plays again. Worse during meal times. Eat 1 spoonful, spit out a bit, suck fingers, lick highchair, turn head away. Continue 2nd spoonful, same scene again. Then completely refuse to open her golden mouth, cry for milk. Give her milk, drink half bottle, reject milk, wants to play. 1hr later continue feeding, eat 1 spoonful, suck fingers, lick highchair, turn head away. I walk away to cool off my boiling blood. She cries. I come back after 5mins to feed her. She eats 2-3 spoonful then starts her nonsense again. So I walk away again. She cries again. I come back after 5mins to feed her again.

The above happens 1-2x daily. Tell me how to keep my cool?

I should attend a "Anger Management" course or dump Miyoko to a childcare centre before I go crazy.