Noise when drawing water

We are away in the caravan at the moment and have had no problems for several days. Yesterday, the water pump has started making a noise when the tap/shower is on. It’s the same noise you get when things aren’t quite connected properly - that sort of high pitched buzzing noise. However, the water works fine. We are reluctant to use the water because it sounds terrible for our neighbours. We have bled the system, and it’s made no difference. The caravan is 8yrs old. Could it be a more terminal problem with the pump? Hope not! This noise continues for some time after the tap has been switched off too. It’s a whale system in a Compass Corona 576. Thank you.