What should I expect out of a second charge of 3rd degree theft?

I recently was caught with attorney, while at work, $178 which happens over a month worth of time. My last charge was a theft from 2011, which was also a 3rd degree with 6 month probation. I feel completely stupid, embarrassed and sick to my stomach over this. I don't know what made me do this which doesn't excuse the matter of course. I had to sit down with a police officer, who had questioned me. I agreed and confessed. He told me he would not arrest me, but would however give me a call and when he did so I would have to turn myself in to the jail, or pay him the $500. Of course I am very grateful that he didn't arrest me being that it was New Year’s, but I have never heard of this before. All that was said was they were going to fax paperwork. I haven't heard of anything more. Being that it has been a few days, it has given me nothing but time to think about my actions and consequences, I'm literally beyond sick to my stomach. I royally just screwed up! What likely is my term of punishment? I am scared to death to go to jail, especially for months on end! My family needs me! (Yes, I should have thought about this before my dumb decision). I can't exactly afford an attorney, unless doing payments which seem to be unlikely.