My True Vault Hunter Mode is Bugged

This is my first post here. I was playing with my friend the other day on my TVHM and decided I wanted to go solo. After rejoining my own solo game, I ended up in the first area with Claptrap outside without his eye. At first, I was confused and tried to use the fast travel station. I had noticed the first mission - My First Gun - had been completed in the HUD display, but the yellow exclamation mark was still present of the gun locker. When I used the fast travel startion, I had no where unlocked (except DLC) I have a few screenshots of the problem.

EDIT: I use a mac to play BL2

Solution 1:

You have to get to the place where you started playing co-op and then you can skip the parts that you've already done.