Sweetheart, you don't get pregnant with fingers unless they are covered with lots of very fresh semen that has sperm inside it that is not exposed to the air. Doesn't sound like that is what happened at all.
For what it is worth, nipples do not hurt a week after sex if a woman is pregnant.
Please get yourself some sex education. I think there are good websites (educational ones, not porno) and I know there are good books.