So a while back, the smoke alarm in the kid's room directly below mine started going off for no apparent reason at 3 AM. Got up, went downstairs to silence it, checked everything in the house, smelled for smoke, looked at all the outlets, etc. Dug through drawers to find a new 9V battery and figured it was either a battery issue or a literal bug set it off. Never really got back to restful sleep after that, and the next day I kept worrying I had missed something and a shorted wire was quietly smoldering away in the wall somewhere.

Next night, around the same time, I was again jolted out of sleep by a loud beep, but by the time I had gotten downstairs, there was no alarm going off, just my ears ringing. Asked everyone else if they heard an alarm, they said no. I must've hallucinated it, but I was also experiencing the most intense tinitus I have ever had. I don't usually get tinitus at all, but my ears were ringing so loudly I couldn't get back to sleep for a half hour afterwards.

I believe I had a major psychosomatic event, which manifested tinitus. It's either that or the timing of the random tinitus that woke me up was a bizarre coincidence.