I went to do The Blessings of Nature quest where you need to get Eldergleam Sap. The pilgrim (Maurice Jondrelle) died in a fight on the way there so I was forced to battle with the Spriggans.
They were beating me, so I decided to just book it, hoping Faendal would follow me. I noticed a while later he was gone but didn't think anything of it.
Anyway, he didn't show up and I killed the dragon, getting Lydia to join me, when I asked her to she said it looks like someones already in my group, so I looked for Faendal, finally found him back at his house after I broke in and slept in his bed.
However, he isn't in my party and when I ask him to follow me he says I've already got someone with me. I think the game still thinks Faendal is following me because I never told him to stay put, or go our own ways.
I've even tried killing Faendal, paying my fine, then getting Lydia. But she still thinks someone is with me. When I talk to Faendal, the only option I have is to improve my archery or have him follow me.
How can I unlock my follower slot so Faendal (or someone else) can join me again?