Potty Training Woes

Leon has got me so confused and yet frustrated at the same time with his potty training. Needless to say, he's in bed early tonight because of it. He is having a rough time...but I think it's more he's doing it on purpose actually. He does great in the mornings at school and then once nap time gets there he suddenly switches modes. I mean...he will have 3-4 "accidents" in an hour. He refuses to sleep anymore during nap time it seems...at home and at school. He will lay down and if you make him stay there he gets mad and just pees...then you change his clothes, ten minutes later, he'll make himself poop. Change him again...and it starts all over again! After nap he does a lot better but the rest of the evening isn't much fun. Tonight he started to have a BM in his pants and then would finish on the potty...twice. I'm proud of him for doing that but extremely frustrated at the same time. 2 weeks ago or so he wasn't having any accidents at all AND telling us before he started to poop. I just don't understand why he's changing all of a sudden. I don't know if it's the change in the class or what. I hate to punish him, but I have to do something to get him to understand that he can't continue this behavior...the pottying or the not napping. Yesterday was the only day in a week and a half that he went to sleep on his own in under 5 minutes...and he got rewarded for that with a sucker. Then, today he does the worst he's done. I just wish he'd go back to the "old Leon" with the potty habits cause I'm over it right now! I just had to vent a little...but I'm also at a loss. I guess I'll do some potty training research or something. I know that he knows what he's doing and is doing it on purpose. If he gets in trouble, he'll sit there and pee his pants too...I just don't get it...maybe we will have the terrible 2's and not the 3's??? I can hope anyway!!