Swimming ("Just keep ...")
"Do you suffer from short-term memory loss?"
It sounds like the prelude to an offer of a medical remedy. But you may become more prone when under the pressure of driving, especially on test.
So … talk to yourself. Reinforce what you're seeing, and what you're going to do about it. Count the numbers of the exits off a roundabout as you go round, so you can spot the one you want.
Keep on swimming; be guided by the current (= the flow of the traffic around you, or arrows marked on the tarmac).