I used to be good. Used to get good grades. Used to always behave. Never shouted at my mum or dad or teachers at school. I thought that I would never start smoking or try drugs and drinking at this age. That all changed when I went to high school and met new friends. I stopped hanging out wif my old friends who were good and started hanging around wif the rong people. I don't want to be this way but I don't know anyone who could help me and I can't tell anyone how I reeli feel inside. I don't even know who I am anymore or what am doing. Everyone finks that am happy because am pretty and popular but there's more to life and there's more to me. I just wish I hadn't met new friends. I love being popular but it's just I've just started finkin bowt the future.
Anyone got any advice?

Find new friends. There is no advice I can give you. You have to stop behaving the way you do. Only you can do it.

For one I think that you need to go back to your old friends or find some new ones. Stop hanging around your current crowd. When you see them at school don't be so friendly with them and keep your distance. They'll no doubt start asking you what's up and you'll have to say something like "I've just got a lot of things on my mind, that's all." Actually, if they're true friends they'll want to try and help you with your "problems", whatever they may be. But something tells me that won't happen. Seek out the decent, respectable kids to be friends with. They may not be the most popular ones but they'll be the one's who'll help steer you straight.

This certainly has a lot to do with it: https://www.askmehelpdesk.com/teens/how-can-get-mums-trust-158092.html

Don't hang out with your new friends find some new ones and the part about yellin at your parents you're a teenager everyone yells at there parents every once in a while

First, all teens go through a rebellious stage (yelling at parents, slacking off in school), while this isn't pretty, it's not unusual. It seems you already know what's wrong, but are hesitant to do anything about it. While you seem to think your new friends are the cause of your actions, I don't recall you saying you are being forced to behave a certain way. If you are already popular, then it's not necessary to go along with bad behavior in order to be accepted (I don't advise that even if one isn't popular!). You can say no, you can choose to do what you know is right. Be a leader, not a follower. And in this way, you will also be a role model. Invite some of your old friends into your new circle, maybe some of their good behavior will rub off on both you and your new friends. Oh, and stop with the drugs and booze. That's not cool, and it doesn't make you cool.