It sounds like you don't feel like your mom is taking your health concerns seriously, and that sounds pretty frustrating. At this point, though, I think it's a good idea to go ahead and try talking with her about this; you really can't know what she might say until you ask.
We have an article that talks about ways to handle medical appointments yourself, which you can read here:
Dealing With Doctors: Taking Control of Your Health Care Destiny It still requires you finding a way to get yourself to the doctor, but this article might have some ideas to help you advocate for yourself & your health with your mom if she's reluctant to make this appointment for you.