Do you think my grandpa did was fair? Am I being taken advantage off?

My grandparents have been nagging that I don’t help around the house, food or anything. I do help with the bills though. I work and do homework so I have a lot on my hands. My grandma says I can make time for other things like help bring food in the house and clean up. I loaned my grandpa $135 and said he was going to pay me back but because he had to get more things we needed he flat out told me I probably won’t get the money back. I told him I didn’t care and it was fine but really I’m upset. He always pay me back. My grandpa said he didn’t want me to think he isn’t giving me my money back but he and grandma can’t be buying food and doing everything by themselves and I didn’t even bother to help so we’re even. I left the shower on for a long time and the bill went up and I had to give him an extra $100 for that became I was being “careless”. I thought I turned it off.
That wasn’t fair! I had to pay extra for the shower! So mean 😭
Autistic people like me always get taken advantage off.