Instance progress lost?

Hey all

Just a quick query, ive been working on Episode 4: The Head of the Snake in LW3

I finally killed caudecus, and had some dialogue and was to go to bedroom, when i got disconnected (no idea why) and i was thrown out of the instance.

When i went back in, i am at the start of the instance? do i need to do all the chain again?

Thanks

EDIT i checked online, and cant go back to checkpoints, sorry for bothering people- would delete this, but it appears you cant delete posts.