i have the same problem - for the longest time i've been completely ignoring my physiological funtions until it started getting really bad, like feeling dizzy or almost passing out.
i'm currently in my 4th year of uni and most of the classes take place in vet clinics, so i had to learn (the hard way unfortunately) that i can't show up to night shifts on 3 hours of sleep and a breakfast.. i also have to look 'presentable' for clients and stuff like that...
anyway, now i started making these mini to do lists in my head (because i feel embarrased to write down in my phone 'take a shower' or 'remember to use your legs today'), i try to eat healthier, sleep more and spend less time staring at the ceiling while overthinking...
having ups and downs is normal but the important thing is that you're trying. i also have this rule called SSS which stands for Soup, Sleep and Strolls - things that having enough of improved the quality of my life immensely, i know that i may sound like i'm 80 but trust me i'm 22.
i'm definitely not the right person to give out advices on this topic, but i guess just try to respect your 'bodily needs' and act accordingly - also don't be too hard on yourself if you fail at doing that from time to time, we all have bad days..
good luck dude :)