Stuff what school say's, just take him/her whatever it is to the vets please! Go to school when you've been to the vets and have an answer.
Please post clear close up pics of your pigs bits on here and we can sex them for you, i would NEVER EVER risk having a male with a female just because the vet says its infertile, as i am sure you know megan, it only takes ones swimmer to get her pregnant then you risk hers and the babies lives if there are complications, what is there is a baby stuck and you have school and cant take her for a few days?
Were trying to help, and i feel like we aren't getting anywhere. I have no doubt you love and care for your animals more than anything else, but when they are bleeding and you dont know why especially from their bits - they need to see a vet with a matter of urgency. How would you feel if you waited to take her because you had school, then when you get in from school she had died, but could have been saved had she of gone to see a vet sooner?
Good luck xx