You already got several suggestions as to what is wrong with your girlfriend.
First of all, pregnancy does not cause blood in pee!!!!!!!!!!!!!!!!!!! That is something wrong with her bladder, kidneys (probably some kind of infection)
secondly, if you do not know what pre-cum is then you should not be sexually active!!!!!!!!!!!!!!!!!!!!!!! Pre-cum is just that, pre-cum. And yes, it can cause pregnancy!!!!!!!!!!!!!!!
Also, it doesn't matter how "deep you are in."
you two need to take sex ed or something and maybe consider being sexually active after you know how babies are made.