Just needed to vent about my job🙄

I KNOW this is what I get paid to do and I’m not sitting on here complaining for no reason, because I really would like advice on what to do because I feel like I’m driving myself INSANE staying at this job. I’m a courier and I get it’s my job to do pointless little tasks that everyone doesn’t want to do, but what I do have a problem with is the feeling about being ran over. I’m the youngest at my job, obviously because I’m the courier, and people always ask me to do things last minute when I’m about to get off or to wait until last minute to leave for runs (which puts me getting off after 5). One day a lady that works in my office ASKED ME TO GET HER WATER! I just went to the store last week for the office and they asked me to go again this week. I feel like the least anyone could do is to check and make sure if we need ANYTHING to put it on the list, and the things I had to get today were pointless, like bandaids and black trash bags when we had white trash bags in the closet and a sponge brush for dishes when we have normal sponges for dishes, and I wash the dishes so what does it matter what sponge we have as long as we have them. They keep adding onto my work load such as extra paperwork tasks and filing, which makes me late for runs sometimes, and I haven’t seen a pay raise yet. I am supposed to replace the water dispenser jugs, yet there are two men in the office that can do it seeing as how I 1. Don’t know how to change it because no one showed me and 2. Can’t even lift the big jug of water up. Today an attorney that is not my boss told me to take care of his documents when that is not my job and I was never trained to do that. Im pretty much stuck at this job at this point because any other job I can get right now won’t work around my class schedule throughout the week. Every time I go to this job my day is completely ruined and I hate it. YES I know this is what I do for a job and I’m getting paid so I should suck it up, but sometimes I just get fed up with all of the bullshit and no communication and feeling of respect and I’m tired of going to this job.