As a glimmer of hope I've finished the game and around the waveboat was the main place I felt bad the rest was fine for me, I also think me being tired was a main cause as well.
Oh I thought of another game that did this to me - Rise of the Tripods (or something like that)
If you are where I think you are try going to the right hand pile near the car wreck near the bridge with the fire barrels under it.
At the top of the pile are three barrels you push out of the way
You'll get onto a roof where two zombies attack then follow the roof around until you get to a sky crane which will put you over a barbed wire fence into the church