Money problems and fruit, vent

This is so embarrassing for me to even tell. My family isn't rich at all and I recently started doing small jobs (earning around 10 dollars a day, without weekeds). Today my grandmother (I don't live with my parents but only with her) asked me how much money I've made since I started, and I said I didn't know because I spend the money I earn (for my needs, not for luxuries). She told me I should buy a printer and I said I don't need one- I am fine with going to the store where I can pay for what I need to be printed. She said: well then you should pay me for all the food you eat: you're the only one in the house who eats fruit and vegetables and they are very expensive. I told her that Mum gave her some money for my expenses but she said it wasn't enough. I don't know... I feel so sad. I went out and bought myself some peaches today and I looked at one I was holding and thought: I bought this, with my money. And I had a bitter taste in my mouth. Feels like the moment I earn some money (and it's not like I'm earning much) I immediately have to give it away. And I go to university, I study so hard to get a scholarship. But still, i feel depressed. I wish I could live limitless for one day