What can be done about excessive sleep? I’m sleeping upwards of 15 hours a day and still completely fatigued

I'm taking multiple naps, I sleep until 1p pretty much every day, it's not because I feel depressed, my body feels like I have 0 energy or life in it. There's no emotion or feelings, nothing to motivate or move me towards waking up. This is disabling me completely, I can't function sleeping this much.