Jesus christ, would you quit already?
I know you think your boss wouldn't screw you over like that because he's a nice guy and he likes you, but he's got a boss too, and if he thinks you're not working out but can't find a reason to fire you, this is what he's going to do to you. The fact that he's nice and likes you is even more of a reason he'd do this kind of thing, becuase, simply, he could be too nice to fire you but not so nice that he'd be willing to take a hit because of it.
You could be making more money as a dishwasher at any joint in town, and a LOT more money doing pizza delivery, and both of those jobs are in industries with unbelievable turnover, so the jobs are certainly out there. But right now you're essentially just wasting your time with this position - if you can't make any money and your boss isn't taking you seriously as an employee, it's time to leave. If you do stick around and simply weather through this bullshit, it's not going to make your boss and the other employees respect you, it's just going to make them think they can walk all over you whenever they feel like it. And to be honest, if I was in their shoes, I would be getting the same impression.
Speaking of easy jobs with infinite turnover, I'm now a full time driver (25-30 hrs/wk) making as much as I was making at my last full time job (40 hrs/wk) regularly, which is roughly 26k/yr. Not bad!