How to access icloud if log in info was changed (new apple ID) due to old email being hacked?

Not too long ago my personal email was hacked and I was unable to access anything from it. I went through the grewling process of getting a new email and updating it on EVERYTHING, including my apple account. I went through Itunes to update my apple ID with my new email. Now every 3 seconds my computer tells me to update or log into my icloud account using my old apple ID (the hacked email account). 1. I dont know the password anymore 2. I cant change the password because it would be sent to the email that I cant access. How do I change my icloud info to the new email (new apple ID) without deleting everything off of my computer?