Did i break a bone in my foot? yesterday i fell walking up the stairs...horrible pains through the top of my foot and instant swelling and bruising

Possibly: While trauma can certainly lead to a fracture, the foot/ankle is a very common site for sprains/strains. If you are unable to bear weight on that foot for more than a few steps or if ther is tenderness to touch a particular point such as the bridge of the foot or the base of the small toe, i would x-ray it to be sure. You can try icing and elevating the foot to see if there is any relief.