Why does everything come crashing down on sundays

I should have known from all three boys getting up at 5:30 that our day was going to be a rough one. But I just thought it would be a good one, or at least I was praying it would. Things for Kodi started off good, yes he was up at 5:30 but he was doing good, ate breakfast watched some TV and played very well with his brother while we were getting ready for church.
I even let him slide down the stairs a bunch of times getting some great input but still he started to melt down when it was time for me to get into the car. This meltdown was a huge one, I was doing everything our therapist had told us to do. I was not talking to much to him, I was keeping myself calm breathing and having Aaron breath as well. He had crawled in front with me and started to push so I let him push putting his legs on the dash and allowing him to push as I pushed back, some very good pressure for him.
But that did not do it, he just fought me harder, than he would get a good swing in and pull my hair and he bit me twice. Finally I got out of the car and let him scream and yell and I told him that I would not allow him to hurt me and I walked away. That seemed to start to calm him down, and things from there started to go better. Needless to say we were late for church. But while I was walking around the yard with him and talking to him we could hear a train blow it's whistle and he covered his ears and it was very painful for him.
He is in total defense mode and we are doing our best to help him. I have been doing more and more reading again and I am thinking he is under stress from us trying to find a school for him, he feeds off of our feelings and we have been very stressed over this problem and I do believe that is some of the problem.
I also posted for some help on www.sensory-processing-disorder.com about his meltdowns and someone gave some great advice about making some yoga pose lion face. So I looked it up and it so far worked. Both boys love making the face.
Let's hope tomorrow is better since we are leaving on vacation for a couple of days :)