I took a job as an admin and was told in tthe interview 8 hours a day after the first week I have been asked to work through lunch and work till 9 at night. I cant do this! Im so exausted working. Ive got 2 little ones at home I am only getting paid 15 an hour too. I like the work I just cant work the hours but they get mad when i try to go home and they slam me with more work the next day please help what can i do????

Talk to the manager with an email or a written letter (this is to leave a proof of your communication). Mention what has been said during the interview. Say that you are having difficult consequences in your family and that you cannot do this any longer.
It's better to talk about it early. The more you wait, the more you make things difficult.