Hello everyone :)  (17F btw)

I'm writing to express some mental health issues I've had recently, to hopefully gain some perspective on methods to help.

I know it might seem to be a shallow thing to worry about, but I just can't seem to feel truly secure in my own skin, and it has been leading to a lot of anxiety, so much so that I had to dismiss myself from school today and go home because I just couldn't stop feeling insecure to the point that my worries built up and lead to an anxiety attack. This was a major issue during my first year of high school, and it has since calmed down, but recently, I'm experiencing the same feelings flaring up, and it has made life and interacting with others so difficult. Every day, I feel like I look ugly, messy, not put together, and simply worse than those around me. These feelings rise to the surface when I'm in a public setting, especially in school, as I compare myself heavily to those around me. I know it isn't true, but I percieve other girls as so much more put together, confident, and secure, to a point where I can never reach their level. The thing is, whenever I return home and look at myself in the mirror, I feel pretty- and I am, according to others. It's almost like I can't point out specific things I feel insecure about when I'm in public, but I just feel an overwhelming sense of general inferiority. I know I'm attractive, but my confidence never lasts more than a few hours. Especially today, I felt extremely uncomfortable in my own skin, I felt messy, like my clothes weren't fitting right, like there was just something plain wrong about myself- all of these feelings alongside me constantly comparing myself to others lead to a small "breakdown", I wasn't present in the moment, too caught up in my head with anxiety.

Is there any way I can find a path out of this cycle? How can I make my comfort and confidence more of a lasting thing, rather than a fleeting feeling? How do I stop comparing myself to other girls when I know deep down I'm a good person in and out?

I'm not seeking definite answers, and I know it takes time and patience to correct these feelings. I just hope I can find a path towards a better mental state.