Overwhelmed

I feel like a failure as a parent. It is taking so long to get B tested for ADD. His next appointment isn't until Dec 4th! I am terrified he will fail the 5th grade. There is so much he isn't taking in right now. His reading comprehension is terrible. His math is just as bad. I am so overwhelmed with everything he has to do. He really tries....and he gets frustrated, as do I, because he just doesn't get it. He is not dumb, it just hasn't clicked yet. It is almost like he gets it, but then when he is at school it all goes away and he has to relearn it. If there is someone to help him one on one, he can do it. I don't know what to do....we have done tutors, my mom helps him, I help him, his teachers are helping him....what else is there???