Forced to stay behind at work last minute

[Char12]

So I've just started a new job in retail and I've been trying my best to make a good impression. Today my shift was supposed to finish at 8, but bang on 8 o clock my manager came up to me and said I had to stay behind to sort out the hangers and security tags/pins/size cubes (literally putting them all in separate boxes, a very time consuming and trivial job). I was told by other managers that it was just something to do when it was quiet. Throughout the day I was told to tidy certain areas if the till was quiet, but the security tags etc were never mentioned so I left them. My manager walked past the till numerous times and didn't tell me I needed to do them until 8 o clock.

My dad was to be giving me a lift home as I live an hour away from my job. I told the manager I couldn't stay and was told I had to as it was my job to sort it out as I was on till last. I did a half arse job and left. I'm dreading going to work tomorrow now and feel like I might lose my job if i'm not flexible. My mums disappointed in me too, staying I should have stayed behind because I need this job.

I travel 2 hours to get to work and was ill last week and still dragged myself in. I'm trying to create a life for myself even when I feel like giving up and I feel like all the effort I put in is for nothing. 

Any helpful words would be appreciated.

[RockoBoy]

I would try to find more clarity from the manager about your actual shift and in reality...what time you usually will end up working til.  That way you might be able to give a better time frame to your Dad about when you'll be done with work.  I realize that your Dad may/may not be flexible, but that's all I can really think of at the moment.  I've never worked retail, but many jobs that involve simple tasks; there is dignity in your hard work.  Hang in there and take care!!