I am being discriminated at work... I am a not a smoker, the other employees are

I work in a fast food resturant... My boss, and the rest of the mangement crew are smokers. They leave me to do thier jobs, watch over other employees,while they are outside smokeing sometimes as much as 7 times in a 5 hour shift. They will stop in the middle of working because, they need a smoke break, leaving myself to do thier job and mine. I have complained of the un fairness before only to be met with nothing as the general manger is a smoker as well.
There is also hassament of my chacator and my job preformance when it suits them to be insultive.
I have been accused of stealing things when I was not even in the same town for 4 to 5 days nor in the resturant at all, Last year the porter ( clean up person) put his hands on my chest and my boss did nothing. I do not know what to do, I have 2 kids to support and I need the job but I have worked there for about 4 years and this is been a contuining issue...

I would apperiacte any help with this and if i have growns to sue the company. I have gone to my general manager's boss and he to has done nothing.