My job is so stressful, should i leave? MATURE ANSWERS!!?

I work in a major New York City salon and have worked every hour i could get to get where i am but now i feel so stressed out. I live in the Bronx and have been offered a job in a lower salon it for everyday people and it is near my fiance's firehouse. He told me to think about leaving my job as it is stressing me out a lot. I have lost alot of weight and am now 7st and my fiance keeps telling me that he is worried about me but i am so snappy lately. Sometimes i have to be in work from 6:30am till 9pm and i don't know if i will be able for it anymore. I lost a baby last year due to stress. I have worked so hard to get where i am and the money is brilliant, i really don't know what to do. Advive?