you want the bar to move basically straight up and down. that means that as you lift it you are going to have to pull your face back out the way of the bar. it should feel like your head is in the bloody way. that is because it is.
i'm stronger at pressing if i lean back a little and use my back, too, but that isn't so good for the back. use your abs to crunch forwards a little (hope that makes sense) to prevent your leaning backwards like you are.