Does this distress you? Lots of people hallucinate by imaging their phone ring or seeing things out of the corner of their eye, for example, but it's no big deal. It's also considered normal to hallucinate when falling asleep or waking up, called hypnagogic and hypnopompic hallucinations respectively. If it doesn't distress you, then I wouldn't worry about it.

All the best

*Willow*