To tired to do anything or is something wrong medically

I am 20 and physically I feel 35 I'm always so tired I get up at 5 every morning go to work leave work for a few hours for class then back to work till 6:30 go home eat shower do homework for a few hours watch tv for around 30-45 min then go to bed is literally all I do every day I don't get to bed till 12-1 am sometimes latter and get back up at 5 and do it all over again I often find myself crashing like I've done a million and twelve things before it's even noon and all I've done is worked and few hours and gotten to class and it isn't even half over I drink coffee but it doesn't seem to help anymore I have no idea how to get over being so tired all the damn time I can't take it anymore it takes every little bit I have just to finish the day and sometimes I'll go to lay down and remember 25 other things I forgot to do and makes it even harder for me to sleep please help I can't take this much longer before my body shuts down from being so tired!!!!!