I feel stressed out

So pretty much when I first started it was fine. By now the place I work at they pushed me into something I wasn’t ready for. If you didn’t know, some places do “home visits” where someone goes to their home. Now i did have an small interest for them. But I genuinely thought that it was just i would go do one maybe once in a while, but no. instead the moment i get my P’s (so ive been driving for like a few seconds) they tell me I have to go and do 15 people all and once and drive all around town. Which was very overwhelming For me. And I have made it clear that I don’t like doing it. And they don’t give me a break! I have to do it every second week, but the week I don’t do i, i do it anyway because the other 1 person is always “sick”. Also i was sick for a few days 2 weeks ago where I couldn’t even get out of bed. and i went home early sick with what seemed to be a stomach bug, and i‘m taking today off to make sure it‘s gone (because I don’t wanna sheet meself) and i get told “it’s happening too much” i know people who take at least every Monday off. And now i feel bad for not wanting to make other people sick. Idk i just feel like they put WAY to much pressure on me. Also im only 19 (i was 18 when i started) so less than a year. But I feel they are already pressuring me