I have similar feelings, although I'm hopeful that Obama honors the platform he ran on and stays just slightly left of center. Clinton did this. He was pretty liberal, but definitely ran the Presidency just slightly left of center. Of course Clinton had a GOP congress to keep him in check. No such luck with Obama.
It actually scares me more to have a one-party system than it does to have a liberal president. Thank all that's holy the Senate Repubs still have enough to filibuster anything that's too far left, like a national police force.
I see this as more a failure of the republican party than anything else. Bush was/is not very conservative as far as I can tell and while I believe it was the right thing to do to go in to Iraq, Bush's reasons were extremely flawed, whether outright lies or just honest bad intelligence. Also the repubs put up some lousy candidates given the climate. They needed someone young and dynamic, like Obama, but instead we got old stiff business men that you could practically see reading their speeches word for word off their teleprompters. Of course they all do that, but Obama makes it look natural.