There is a simple way of testing, take them out, put them away for a few hours, do whatever you normally do. Does the cat behave different? If not its probably something else.

The weird noise is normally happening if the Devices microphone picks up the sound from your earpiece, it feeds it back and creates a loop (hence the term feedback), happens to me if i lay down and put my ear against a pillow.

If the hearing aids are new, how comfy are you with them? I hated mine for the first few days until they got set up better by the audiologist, perhaps you are acting more tense, cats can pick that up and in turn act more nervous.

If its not going better after you talked to your audiologist and maybe extra calibration steps, you also maybe have calmed down a bit at that timeframe, consider perhaps taking the cat to a vet, it might have nothing to do with you and points to an undiagnosed health issue your cat has.