Why would a 1998 dodge laramie slt get hot after changing the serpentine belt?

i changed the serpentine belt on my truck after it broke. it was running when it broke. changed the belt and its on right but now its getting hot. never got hot before. please help|||the belt is on wrong, and running the waterpump backwards.....|||is it possible you have the belt routed wrong on it because sometimes you can run them the wrong way,that or a bad thermostat would be the two most likely causes for sudden hotter temperatures,good luck.