I'm assuming that your parents want you to do well academically. You should remind them that it is difficult to learn if you sleep through class. That might sway them.

Also, don't let guilt over the cost sway you from pressuring them to take you to the doctor. If you have good insurance it should be affordable. With my parents' plan, a primary care appt. is only $25.

Just to be warned: your doctor may make the same assumptions as your parents, that the fatigue is due to depression or your meds. Unfortunately, a lot of people with MI receive inadequate medical care because some doctors find it easier to blame new physical symptoms on a pre-existing mental illness. Make sure to tell your doctor that you are not depressed. That knocks down one possible easy explanation.