I've searched the whole map, but I can't find the springberries to make my illness go away. Whereabouts are they?
I've marked them in red on the map here, they're just behind the wolf that attacks you:
They're at the Northwest corner, just past where you fought the wolf(wolves, depending on difficulty.)
If you're having trouble spotting them, remember you can hold down tab to highlight interactive objects, containers, and NPC's in the area.
The other answers pointed out where to find the berries, but it's worth noting that you can actually progress in the game if you don't want to faff about hunting for them. You can simply start murdering the caravan right from the start and your quest objective will change.