should I quit my job? (lack of hours?

I've been with the company for almost 2 years now.I recently transferred to a new location out of state,and at this one we don't make much business I understand that but what I don't understand is how the hours are being shared?..Since I began working at my new location in February I wrote down that I am available from 7a.m to 9.pm at night and on weekendsI can work any time... Recently they hired a new guy, out of no where he was employee of the month.. I didn't even know we had an employee of the month! well this guy has been given the hours I USUALLY WORK ALL THE TIME 7A.M-3P.M even though he started a month ago and they've given me those hours since I started working there now I'm home all weekdays until they need me to a closing shift on the weekend which is probably every other weekend! I don't understand why they keep hiring employees when we don't make enough business ?