Cannot stay awake no matter how much I want to.

17 years old, \- Can stay awake for work, can usually stay awake for school \- Taking iron supplements for iron deficiency \- gym at least 2x per week \- 5:50 am wake up/ go to school-> After school I sleep until 8pm, do as much homework as I can until I get tired -> sleep at 11pm \- On weekends I get up at a reasonable hour 8/9 am, still get very tired midday \- I get tired after I eat \- I get tired from doing nothing, usually not enough NRG to do anything, just lounge around on my phone/hangout with my dogs It’s genuinely ruining my life, my grades are slipping, I’m gaining weight, it’s unhealthy, and it feels out of my control. I’ve already tried forcing myself awake during the day, only works for 2 days straight with max effort until I need daytime sleep