SureAI

The first Levelup (ability to level up), is unlocked when you kill the Black Troll. There might have been an error in the quest, vause you used godmode, and thats why you cant use the journey book.
Can you upload the savegame? Maybe we can find a way to fix it, else you really might have to start over.

Btw, cheating is never a good idea while questing. There are a few more quests that will get destroyed when you are in godmode doing them. Be careful.

I think you need a quest log cheat!
ask arvisrend about this i think he now the name of the cheat

I've started a new game and leveling up seems to work fine. Already level 3. Too bad I spent 5 hours on that other character though

It wasn't because I used godmode, I know that - I loaded all four of the torch holders with torches and the black troll just stood there on fire. I would run up to him and hit him a few times before running away and healing, but his health was barely going anywhere. I know now that loading the four torches should have killed him instantly, as it did in my new save game, but it didn't for the first one. Oh well, it's no big problem, my new character is coming along fine. It may have been an issue with patching, but I'm all patched up now.