I think there is a glitch in my game. I can't hire a troll, the guy says I already have one following me, but i don't. Is this because of Serana or is it a glitch???

Serana's a troll now?

LQTM

Probally a glitch. Can you dismiss your follower at the moment? It may fix it?

Or fast travel and kill any animals nearby, like a dog, if not a troll.

I'm on a quest where she forces herself as a follower, but i can still get Dawn Guard members to follow me. I killed all the trolls in the fort so i think it is to late