macbook pro/ipod touch asks for icloud password after OS (el cap.) update

Yesterday i installed the new OS updated and everything was fine, worked on my macbook and eventually shut it down when i went to bed.

Today, i seem to be locked out of my macbook as it asks for an iCloud Password and redirects me to the appleid.apple.com website if i want to change the password. So i log in with my AppleID and change my password thinking it would work and i could login again.

Im thinking, that my macbook might be connected to my old AppleID which i dont own anymore. So i read everything i could find on google this evening. I tried a lot:

1) changing the primary email adress to my old one again. apple asks for verification email but i cant access my old email so this option is out.

2) comman + r on macbook for a reinstall of el cap. > didnt work.

3) booting safe mode > didnt work.

-- at this point of the evening i was thinking about a factory reset of my macbook but i have files on there i need

4) check time machine thing, but i didnt do a backup so > my bad.

5) trying to access iCloud on my PC so i could access my iPod touch 5g or macbook > asks for old email and password which i dont own anymore and cant access

so.. how do i get back on my macbook and how do i change my AppleID to my new ID on my iPod touch even though i dont know my password.

Help is very much appreciated. (also sorry if this is the wrong forum)