My job is already getting annoying.

Last thursday, I got my schedule for the week from Canadian tire and I wasn'st scheduled to work until wednesday. I thought that was pretty sick because I wouldn't have to work for almost a week because I was new. But sunday afternoon, at around 3:00, I get a call from my work, my manager told me I was scheduled to work that same day from 2:00 to 6:00, but it wasn't written on my schedule so I was really confused and frustratred with them because I'm watching a movie and just relaxing and then I get a call from them saying I need to get to work as soon as possible. So I'm there like freaking out a little bit because my mom isn't home to drive me to work and there are no reliable buses to take me there. So I get ready and hope that my mom gets home fast, then I decide to call them back and just tell them my mom isn't home yet and they told me to run to work. As if I was going to run in the freezing cold for two hours. I asked if I was going to get fired for that and he said no wich is a really good thing, I thought it would make me look like a really bad new employee. So thankfully my mother came back home around ten minutes after and I told her to step on it to get to work, I got there at around 3:15 and just got to work. So, I worked my entire shift, wich should have ended at 6:00, but they made me stay until 7:00 because I had to close. So now, even if my schedule says I finish work at a certain hour, I have to stay an extra hour later. Oh and I have to work a ten hour shift on saturday, so that should really suck.