You need to see a counselor, maybe get on some anti anxiety meds. The bad part is that you're going to keep becoming dependent on this way to cope, and then you're going to have it worse and worse to quit. You're having anxiety attacks for a reason. You're going to have to figure out that reason and deal with it, period.

The stress you're feeling is fueling them and making them even worse.

Try to talk to the school counselor first, they might be able to help with planning how to get through school. Needing to take a break to take care of yourself isn't a failure on your part, it happens to a lot of people, you aren't the first person they've had to help and you won't be the last.

It doesn't sound like it's going to get better on its own, it's going to get worse. Please please please talk to someone.

I notice you're 15. I was 15 when my parents found out I cut. If you have any questions, I'll do my best to answer what happened. Please get help.