I work for take out at a restaurant and I only get paid 5.75 an hour but my tips are not gaurentied , is that right? Am I getting underpaid?

Depends on your location.

What state?
There are several exemptions to the federal minimum of 7.25/hr, plus each state has their own laws that do not override federal.
If you are paid less than 7.25 because you have a job with tips, then your pay with tips must meet the minimum. But your employer might have another kind of exemption.