They're not required to provide you with a break room. You deal with it or find a new job.
edit: Yeah, she can deal or go. And don't address other answerers. Simply answer the question you came to answer.
@Little Red Hen: That is quite a hateful answer you gave and work isn't exactly that way.
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Your age and where you work makes no difference. The US Dept. of Labor says that if you work an 8-hour shift you get a 15-minute break in the morning, a lunch break, and another 15-minute break in the afternoon. If you work 5 hours you get one break.
You are overdue to have a talk with your manager about getting your breaks and ask him/her to assign you a time for those breaks. If there is no break room then it's automatically assumed that you sit in the public dining area for them. Don't assume anything, ASK; they can't fire you for it.