Any educational establishment should have a support department for issues like this. If we're wrong, then I advise speaking to your mental health care team (or your doctor) and getting a note or further guidance on what to do in your situation.

I had support with my bipolar throughout secondary school (12-16) and college (16-17) and I am pretty sure that your high school will have something similar. I'm fairly sure, also, that it would be against one or two disability & equality acts NOT to appreciate your situation.

Like I said, doctor. But also try asking at the high school main office/reception about a disability office/department.

My college was always very understanding and made sure I knew that if I needed one or two days off whenever to cope with my bipolar, I should do so without feeling guilty or worried about losing track of work.

SunAngel is right, there should be some kind of learner/student support department at your educational establishment. Go there and discuss your bipolar disorder and how it affects you. The thing is...it is actually VERY important that we get some rest when we need it or it could trigger a full blow depressive (or even manic) episode. If you discuss this with the RIGHT person (namely somebody within the disability/learner/student support department), I believe you could sort something out.

It's important not to take too much on, and some teachers/lecturers unfortunately do not understand this. There will however be a department somewhere in the place to actually speak to and discuss everything with somebody that does understand. Get your rest.

Keep us posted
RB ♥