Masturbation?

I am 17 and a half weeks and at about 15 and a half weeks i was masturbting and afterwards when i went to pee i had a very strong sensation down below---like three sharp pains. did i hurt my baby? am i a candidate for miscarriage.. I am very scared. 1st pregnancy and i go back the dr. for my sonogram on the 3rd. i don't want any bad news.