on my oblivion game it says there is an enemy nearby and it wont let me fast travel or wait and there is no enemy what should i do

save your game and reload it and if it still says theres one near there may actually be one near, in that case i recommend just walking until you can.

Go into a city, pick up a bowl, get arrested, go to jail, if the enemy really wants to kill you, they'll pop up after you get out of jail and they will most likely get annihilated by the local guards. More often than not, you'll come out of jail no worse for the wear, with no more "There is a monster nearby trololol" message.