coke rant: i'm on this job for 1 month and a half

and my assistant (i'm her boss) barely comes to work ever, she's always late, she always leaves early who has to cover for her hours? me... i cant just close and go home, i have to keep the library open and stay extra hours. i work for about 5 hours more than i should weekly. i'm absolutely exhausted...? like i was supposed to be home by now but she just left cause she has a son and thinks thats a free pass for her to leave and arrive anytime she wants. the direction/staff is hiring someone for her spot for like a month. sometimes i feel like its all a prank because i've never been a great student in college. like i was always quite mediocre and somehow i never stayed unemployed. they're all just pranking me for some reason like they wanna see me work harder or sum oh and the library is a mess. i work twice as hard because she often just bails on me, i have to do my work and her work, and of course its not a good work, its a sloppy work by one person that is meant for two (or more?). there are several issues i should be resolving and i'm not because she is supposed to not let me drawn in overwork but it just never helps