Fallout 3: Is there anyway to reload if i mess up?!?

Basically in Rivet City me and my friend had some fun shooting everyone including important characters who i presume are vital to the game, then went though a door and it SAVED! NOOOOO! My last save point is 2 hours back and takes ages to get through as i have low health and there are lots of super mutants so is there anyway to start back at Rivet City with everything ok again?!