Experiencing unusual sounds or sensations during the transition between sleep and wakefulness is not uncommon and is often associated with a phenomenon called "hypnagogic hallucinations." These hallucinations can occur as you are falling asleep (hypnagogic) or waking up (hypnopompic) and are typically brief and vivid.
Hypnagogic hallucinations are thought to be a result of the brain remaining partially in a dream-like state while you become conscious. During this transitional period, sensory perceptions can become distorted, leading to auditory, visual, or tactile hallucinations. These hallucinations can vary widely from person to person and may range from simple sounds like tapping or buzzing to more complex and vivid experiences.
Common triggers for hypnagogic hallucinations can include sleep deprivation, irregular sleep schedules, stress, and sleep disorders like narcolepsy. They are generally considered to be harmless and not indicative of any underlying mental health issues.
If you experience these hallucinations occasionally and they do not significantly impact your daily life or cause distress, there is likely no cause for concern. However, if you find these experiences are becoming frequent, disturbing, or affecting your sleep quality and overall well-being, it's a good idea to consult with a healthcare professional or a sleep specialist for a proper evaluation.
It's also worth mentioning that the content of hypnagogic hallucinations can sometimes be influenced by external stimuli or sounds present in your environment as you start to wake up. So, in some cases, the sounds you heard during your experience might have been actual sounds in your surroundings that your brain interpreted in a unique way during this transitional state.