I do not think you are crazy at all... you were freelance and started the company because you like that sort of thing, presumably, and now that it is more stolid it does not have any appeal. It happens a lot.

That said you will want to handle this professionally so that you do not burn any bridges. You have sold one company and may want to do it again so you will need a reference there.

I remember reading that when Jim Clark wanted to leave SGI (prior to founding Netscape) he spent about 6 months working it out. Obviously your situation is different but you may want to pickup his book Netscape Time and read the sections on his exit from Silicon Graphics to see if there is any advice there that you can use.