fear of pregnancy, help please

my gf and i were rubing against each other and got intense, i was beginning to pre-cum, but there was always at least my boxers and her underwear between us, what are the odds of her becoming pregnant? later i briefly was rubbing her and i might have touched the pre-cum on my boxers a little before, what are the odds that she could get pregnant from that? how hard or easy is it really to get pregnant? how much sperm actually makes it from ejaculation to where the eggs are? am i just way over paranoid?