Little Black Rain Cloud

Sometimes my youngest son has a lot in common with Eeyore. He has a habit of thinking that bad things are always going to happen to him. At the start of church basketball season he predicted that he was going to get his nose broken during the season. Sure enough, it didn't take long for that very thing to happen. I kind of think he wanted it to happen, but maybe not.
When the son and I went to the oral surgeon to discuss having his wisdom teeth pulled the doctor shared with him all the possible things that could go wrong. He told him the most likely was that he would get a dry socket, which is where the blood clot that forms in the hole where the tooth was dissolves and leaves the nerve exposed to the air. It can be very painful but is easily treated. As we left the office the son told me, "I'm going to get a dry socket." When I questioned why he said "that kind of thing always happens to me." I suggested that he have a more positive outlook and even made a bet with him, if he got a dry socket I would wash his dishes the next two times it was his turn.
Day 2 (the most common time for a dry socket) passed with no problem. Day 3 - no problem. Day 4 - no problem. Day 5 - there was more pain than usual on the left side, but even the son didn't think it was a dry socket because it didn't hurt as bad as the dentist had said it would. Day 6, Monday morning (first day back to school after spring break) the boy's pain level on a scale of 1 to 10 was 27 when he woke up. He took an Advil and said it helped a little, but not much, but of course his mean mom still made him go to school. I called the doctor and they said bring him in, so during his lunch hour we took a trip to the the oral surgeon. It was most likely a dry socket. He was treated with some nasty smelling, nasty tasting dry socket paste that took the pain away in about 30 minutes. We get to go back every 2 days to get more medicine put in for at least a week and I get to wash his dishes as well.
Same thing with the son's report card. He thinks he's going to get bad grades and sure enough that's what he gets.
I need to figure out a way to get the kid to envision positive things happening in his life. Think of all the good things that could come to pass if he'd just think them.