Not sure if this is a bug, or what, but here's the scoop. My latest build is a priest. I always travel with companions and they do the fighting while I buff, heal and cast illusion spells. Anyway, Svengar and I are clearing a Giant camp, and Svengar keeps charging in, while I'm trying to kite. So I tell him to stay put on top of a hill. Well the Giant gets to him, and launches him into orbit, buh-bye Svengar. I can't find his body.
A couple of hours later, I try to hire the dark elf in WhiteRun, she says I already have a follower. Then I travel to Rorikstead and try the same thing with Erik The Slayer, and he says the same thing.
So I'm thinking, well maybe Svengar somehow survived the Giant smash and is just standing out wherever he landed because he is a good listener, so I fast travel to where it happened, and spent 20 minutes walking around looking for his body. No dice. So I'm screwed now. At level 21 and 40 hours in (add another 225 or so to total playtime on other characters) my priest build is scrapped because I'm stuck with a follower who just isn't there.
Suggestion: Put a green blip on the map to show us our companions, or under Active Effects show the name of the follower and then give us the option to unequip them. Thanks!

PS, I'm on the Box so no mods for me, or cheating ass console commands, but alas it would be nice!

There is a bandaid which lets you track your followers. Get a collection quest, like the one where you have to collect 10 bear pelts for that woman, give one of your pelts to the follower, they should now appear on the map.

Oh and make sure you track the quest.

That's clever. I would've liked to have known this before this happened....I guess it's back to simply blasting all badies with OP firebolts for the rest of the game. And I was having soo much fun playing a support class...