The German, who finished eighth in the season-ending Japanese Grand Prix to secure the one point he needed to ensure he took the title, said the race was one of the toughest of his career after starting 14th and struggling to get in the points.
"It has been a tough year, a tough late stage to the season and a very tough race," he said after celebrating the title without a podium appearance.
"Probably one of my toughest."
"I was a little bit messy today after having a little incident, and that's why I said it was one of my toughest races because to come back then and go through the traffic and fight your way through with all that happened.
"It was a very, very strange race and therefore the feeling hasn't sunk in yet. I can feel well for the team but I can't feel for myself at the moment.
"I am empty and exhausted and just proud of what we have all achieved."
Ferrari beat Williams for their fifth constructors' championship in a row, while Schumacher's title was his fourth in succession for the Italian team and the hardest fought of them all.
Last year the German was champion with six races to spare and with a record 11 wins. This year he has had six victories and been pushed all the way.
On Sunday, he collided with Takuma Sato's BAR and then skidded under braking behind the Toyota of Brazilian Cristiano da Matta. The Williams of Schumacher's brother Ralf hit the Ferrari's rear left wheel.
"I could rely on Rubens in the late stages but I still had to fight as you never know whether a car will finish," said Schumacher.
"We are in Formula One and we have always seen things happening in the past, so you have to think about the worst to be safe and that's what I was trying.
"The fight with Cristiano and Ralf and myself in between was quite a tough one and I really had to try to make sure I stayed and got that eighth position to score the point," he added.
"It is very strange for me because most of my championships have been with a victory and here I am winning with eighth position."
Schumacher said Ferrari were like a family to him and praised their fantastic efforts, particularly after much of the Italian media had written them off as a team in crisis after the Hungarian Grand Prix.
"What we saw in Hockenheim and Budapest, how many people wrote us off, how many people wrote things about us, outspoken things," he said. "And here we are, we're back. We never give up.
"We're always there, we always fight and I think that's one of the big strengths of the Ferrari team. Everybody in Ferrari is that way. This is just a huge family and we are all proud of being a part of."