not sure what to do

[pinetop]

first off i didnt know where to post this but i guessed here
ok so heres whats going on in my weigh lifting class
we do this thing called a dot drill heres a example of it
http://www.youtube.com/watch?v=PR7s4nXtWSw

its that well heres where the problems come in
so the teacher splits us into groups of 4 we do this when he says go and we see our time and its in front of the whole class
well im terrible at this dot drill i cant do it it takes me like 7 minutes
i dont know why i just cant do it im kind of chubby so this dosent help
the last time we had to do this i had to go last and the whole class was watching and i falied and fell and everyone made fun of me
we have to do this next week and im very afraid because i know i will fail and everyone will laugh at me i tried to talk to the teacher but he just said ill do better this time which i wont the thing is he wont tell me which day of the week it is next week cause he knows ill not go to school
that day i really dont want to do this as i dont want to be embarrassed again i arleady talked to him and he dosent really care
i just dont know what to do