I told a homeless person to get a job and now I feel bad

I'm a server and I had a table that I asked if they needed anything other than their check. The man at the table told me that they were a couple and they were homeless. I asked how they were able to afford to eat dinner at a restaurant if they were homeless. He asked me if I could comp their meal. I get a 5% discount on food. I told him I do have a 5% discount. He didn't seem to happy. I honestly don't like giving people free things and I don't make a lot. I have 3 kids and a wife trying to provide for. So I said something along the line of get a job or something not trying to be mean. But now I feel horrible. I don't even make enough to support my family. I don't have extra money to give people. I feel bad though. What should I have done ?