AITAH For not wanting to spend my money on my brother?

So we’ve come on holiday and me and my brother were both given £25.
I’m terrible when it comes to spending money for the sake of it so I squandered all of mine. Because of this I didn’t have enough money to buy the things I actually wanted which was my fault. My dad also took £20 off of me which he said would be for my brother so I didn’t spend it, I was going to make sure he still had his share of the money. They were also quick to have a go at me when they thought I’d dug into his money when I hadn’t.
I got given an extra £25 by both my parents.
Today my brother came up to me and asked me if he could have an icecream, so I said “dad has your money go and ask him.” My brother went to ask my dad who told me that I had to buy it for him with MY money. So it’s ok for him to spend my money then? When I said that this wasn’t fair because he’s still got his money left I got into trouble and now I don’t want to go back to the caravan tonight because I know there will be another argument.

AITAH?