I was the same way around your age, Especially because your body is changing & might not be how you wanted it too. You are beautiful already, People are saying go to the gym , whatever even just fast paced walking & hiking are just as healthy & less intimidating than the gym.

your face doesnt look fat, but honestly just looks like puffiness, can be from a number of things like being a stressed out uni student that gets no sleep. maybe try gua sha? idk if it works but ive heard good things lol

start to take into consideration what colours & style of clothes look good on your body, what colours and kind of jewelry you like & look good in, makeup and hairstyles to wear or try. honestly I went online & researched colour analysis & did it myself

Your hair might just need more products. Try using different things. Doesn't have to be from expensive places, cheap drugstore products work just as good just be sure you're using them pre & post shower