First day of school not too great

Well, it was not too good of a start. The methods they use are good, but, well, he is not responding to some of them. He is fair with "watch" "sit" and sort of good with "heel". He still pulls like the dickens however when he knows I do not have a treat or we are just normal walking. They say not to use my Easy Walk Harness, but I am as long as I am home, otherwise, it just hurts my already painful back way to much, for being so light weight, he can really pull. As to "Down" he just will not do it, I have to literally get on my hands and knees and shove him down. All the other dogs were responding to the way the trainers said, which is to have him sit, then hold food between his legs until he lays down, well, forget it, this did not work, no matter what they tired, he would not do it, I was almost in tears. This morning, I tried my own method, and he was better. Also, he did not want to take his eyes off of Steve who was standing at the side lines, and near the end of the class, he got so hyper , he was barking and howling and straining on his leash to get to him. I told Steve to please leave, but that did not work, he could see him way across the field and he really got upset. I am almost in tears over this, I mean, he loves everyone but me, it is so obvious. If we are alone, they he is fine, but let ANYONE, and I mean ANYONE come near him, and I am chopped liver. This is getting old.
The classes are 7 weeks long, I hope we pass, but if yesterday is any indication, it is not promising. At least he performed better this morning at home.
He is just so hyper at school, he is not afraid, but, he will not listen to me at all, the other dogs, who are all more or less younger than he, even listened better, there may have been a few that did not behave, but all in all, they were very good. This cute little Samoyed, already would go down on command and sit, he was only 3 or 4 months old.
Oh well, hopefully all will get better. Does anyone have any ideas on how to teach "down"?
