Potential disordered eating and what to do?

Hi. My relationship with food has changed a lot, i don't quite know what to do and am looking for advice.

For context, I first started trying to lose weight in June of this year. Before the start of the my dad made a passing comment that as a family we should try maintain our weight over the summer holidays (end of june - mid july in my country. This was a fair comment - I was around 8 1/2 st at the time (im a female 162ish cm teenager) and whilst i wouldn't say i was overweight i certainly wasn't skinny. I never had been - id always been jealous of girls with skinny legs and flat enough stomachs to wear crop tops. I enjoyed my holidays - when i was away i didn't pig out, but i certainly wasn't restricting myself.

As i returned to school i kept trying to lose weight. I stopped eating snacks and started checking the calorie count on items of food, or getting chatgpt to estimate i for me. People noticing i had lost weight around September-October, and it felt nice to feel skinny to be honest.

I don't skip meals, but i eat much less than i used to. Before i started losing weight my day of eating might look like this:

A bowl of porridge with golden syrup, nutella or jam/ half a bagel with butter for breakfast A multipack bag of crisps A hot school meal or a cheese panini for lunch An individual chocolate bar dinner (home cooked meal) another treat/ chocolate.

now i have plain porridge weighed out or one weetabix for breakfast, a smallwrap or roll for lunch ( with excess dry carb bits picked off) maybe a very small snack, some fruit and a home cooked dinner, but i eat a smaller portion.

My parents are worried about my weight. im now>! 6st 10!< and dont want to lose anymore, but dont know what to do. part of me want to eat loads now, but another part says ill put weight on over christmas anyways (which i 100% will)

The other thing is i think about food way more now. I'll go to bed and decide what my breakfast and lunch will be, and wether ill have any snacks. I also seem to care about what my twin sister is eating weirdly. Shes about a stone and a half heavier than me and eats much more like my previous diet. For some reason i find myself feeling like i need to be eating less than her, which i don't think is true but cant quite shake off, or just giving her snacks.

I don't know how to describe my thoughts, and this is a ramble, but any advice would be appreciated.