I really really hate my job?

Im 18 years old and i have worked in a warehouse for the past ten months, when i first started the hours i worked was 6am - 4pm, which i found was disturbing my social life by knackering me out, the work we do is physically draining, in recent months the hours have become 6am - 2pm, which is alot better but you dont get the rest of the day to yourself because youre too tired from being up at the crack of dawn, and last week they made us work 6am - 6pm, which is just pathetic considering the work we do physically knocks you out, i work for an agency and they treat you like scum, they even threaten to terminate our contracts if we dont work Bank holidays, im only yopung i dont think i should be doing these mind numbing hours...???, my parents always pressurise me saying they need my help financially and if i dont contribute money wise we will have to get out of our current house, what should i do? because im am inch away from blowing, im gonna quit =/