I'm scared that I'm gonna hate myself after high school
What is your reason for feeling you may hate yourself after high school?
It is just a negative thought that I tend to have.
You shouldn't hate yourself, but the good news is, that this is very rare.  I'm sure you'll accept yourself after high school just as you do today, but if you do feel resentment, there are people who can help you work it out.
I don't have many friends so they might not be able to help me much. After high school, I'm just going to leave my town before I start hating myself. My friends are not that mean so I don't feel any resentment towards them.
Try your best to learn to love yourself and who you are. There will be things you dislike, but you can improve as a person the best you can. Try to find peace with just giving your best effort each and every day in life.