My alarms keep getting turned off

This started happening about a couple of months ago. I would set alarms and the next day they randomly wouldn’t go off. But when I would check the alarm it would be shut off. Some of these alarms I set after midnight so I know it wasn't like it went off in the day and didn't go off because I silenced it or something. There are several alarms that I checked and double-checked to make sure that it was set because it was super important, and once again the next day it would be turned off when I checked on it. I feel like it's some kind of hack. But I wouldn't know where to begin. No one has access to my phone except for me.