I don't know what's wrong? My family life is awkward?

[Frankie]

Okay, I've been pretty confused lately...according to my parents I've been showing signs of depression, and to be fair I can see that, I've had major mood swings and especially been in a really emotional and low depressed mood since back in July.
My mum thinks there is something wrong with me or I'm just attention seeking... But honestly I have no idea whats wrong...I just like being on my own quite a lot. I'm really self conscious.
I do have social media sites on my phone and spend most of my time in my room on these sites talking to my friends...however my parents because of my mood have punished me by taking my phone and laptop off me so I can't talk to them in my free time at home, I could pick up the phone and call my friends but it's not realky something we do...plus I see them every day at school so I do have physical social time...anyway my parents said that I can't have my phone back, they're going to cut my allowance and ban me from my room unless I tell them whats wrong...it's really stressing me out because I don't know what's wrong I honestly don't...I just feel really upset and emotional. It might be hormones but I don't actually know what's wrong. I'm really upsetting my parents and I'm not meaning to. I just don't know what to say to them or what to do to make our household a pleasant place not an awkward and hostile environment :/
Im 18 by the way