The First Time I was The teachers

The head teacher come into my class and told us that our teacher was sick,today."Therefore,I was going to chose a student to teach the class today."he said.
To my surprised ,he chose me.So , I went up tom the white board and taught them with a very good lesson.For example i was giving them to do the exercise with a lot of grammar vocabulary .Also some writing and reading too.Additionally some of the student they didn't like to study so i play a game that connected with study .
Nearly time to go home . I gave them to work in pairs doing conversation to improve their speaking,however i don't think that my speaking is good.Moreover i give them to speak English class.Although some of the student didn't do what i said and they bother the class.I really angry so i told them to stopped bother their friend ,listen to me and try to speak English because it is English classes.
Do you know what do i feel the first time to teach English to classmates?I feel very angry and stressful.