OK, were you diagnosed with Cancer or Dysplasia? It sounds like you have displasia (since they don't diagnose cancer with a pap smear, they do the test it sounds like you are going to get where it tells you if it is precancer or cancer.).
I have had cervical cancer and, sweetie, relax this is just the very begining. Cervical abnormalities are so very common. It sounds like you are turning cervical dysplasia into 'cancer' when it is very, very far from it! In fact, it can take decades for dysplasia to become cancer - if it ever does. It isn't a guarantee that it will become cancer but it
can.
That said, you'll now go in for a colposcopy where they numb your cervix, put some stuff on there (similar to vinegar) that turns the 'bad' cells white. Your doctor will take samples of these 'bad' cells and send them off to be tested. When they come back, a decision is made whether they'll be removed or if that is even necessary. Some doctors use a watch and wait approach. Some dysplasia can go away on it's own.
What has caused this? Human Papilloma Virus. It is the high risk type of HPV. The lower risk kind causes genital warts. Neither can be gotten rid of, but they can be controlled by your body.
Cervical abnormalities do not effect your fertility. The only thing that potentially
could would be if there was signifcant scarring on your cervix, causing it to close up. Though that is so rare it isn't worth worrying about.