Rant about work

Ugh I have just started at my new job and in totally fed up with it! I work in the lab and I'm by myself. I draw blood all day and process specimens I work from 8-4:30 pm not bad right? Well that 8 am turns into 7:30 am and that 4:30 pm turns into 5-5:30 pm. 7 days a week. I end up working 50 hours a week instead of 40. I end up helping the other medical assistants out when they don't help me. I end up filling in for them when they call off and I have to close down my lab for them.