There is no risk of using clippers. The previous event was likely a stimulation issue, not a physical vibration/movement issue. The sound can be just the wrong frequency that resonated into your ear. The reaction is a anxiety / fight or flight or freeze response.

Stop sleeping during the day and your night time normal sleep will improve. Some need some food in the system shortly before going to bed to energize the brain so it can sleep. REM sleep uses a lot of energy. It is when neuronal healing/repair occurs.

If you feel tired during the day, it is usually because you are not getting quality sleep during the night. If somebody can observe your sleep during the night, they may notice breathing issues. You can buy a recording pulse-oximeter that reports to a smart phone to track oxygen levels and pulse. It can be helpful at understanding sleep issues. A FitBit will track movement and pulse.