Was it wrong for me to not go to work?

I think my contract has expired, I was only there for a couple of weeks to help with the sale. It was my first job and I think it ended last week but they called me the other day to help out again. I hate work because I'm not a social person and they people there are very rude and all seem to have an attitude, but I want money to save up for a tattoo. I was meant to work an extra day yesterday but I stubbed my foot really hard against something and it got swollen. I kept waking up in the night from the pain so I don't know if it's bruised, broken or sprained. I wanted to go to work anyway but I got half way down the road, all these old people were overtaking me and it was agony to walk so I called work in sick. I told my mum before I left that I wouldn't be much use and I thought she would say that I didn't have to go but she said I should go and let them know when I was there so I'd be limping and working slow. When I told her I couldn't make it to work she acted distant with me and said I was letting people down.. But I'm just a worker to them who they don't treat very well and who I'm polite to but meh. That isn't the reason though, I mean I want the money. I feel guilty now, should I have gone to work?