The real cost of taxes

I work in the oil field as a offshore surveyor. I make roughly 400 dollars a day. If I was to quite my company and go contract I would make 600 dollars a day but I wouldn't cost the company I work for a dollar extra. I started thinking about it and by my calculations at a 25% tax rate I am paying out the butt in taxes. Lets say I cost the company 100 dollars a day but after they paid all my so called benefits they which is 1/3 I only make 66 dollars a day. Now after they write a check for 66 dollars the government takes out 25% which goes down to 49.5 dollars and then the jerks charge me 13% for social security which takes it down to 43 dollars. I guess I might as well figure in a 8 percent state income tax which would put me down to 39 dollars..... So if I am getting this right We only earn 39 cents on every dollar that we make due to taxes and thats not even considering the sales tax.... I might be wrong on this but jeez if this is the case then whats the point in working....