I'm terrible at school and scared it will impact work in the future.
Can you explain to me what you mean?
I'm terrified of not being able to earn a living with my school record.
Find a tutor or a study group for yourself so you can do better in school. Better grades will give you a better chance of getting a good job.
I'm just going to drop out, this is hopeless.
There are ways for you to get the help you need with school. Look online, ask teachers, and ask other students. People will help you out if you need it.