lost all photo stream when i opened icloud

So, a few days ago i received my new apple macbook pro.

however when buying it my mum entered her email adress so she could receive the receipt. When my macbook was then delivered everything on it was configured to her!, I've now sorted this out (but i thought i'd mention it incase it was relevent)

anyway i went to open icloud, verified my apple id and looked at my iphone, and all of my photo stream photos had dissapeard!

just wondering if these would have gone into icloud or something?

how can i retreive them, cause there are some very sentimental photos of my family which i hadnt backed up yet :/

Thanks, amelia