Honestly, I will suggest talking to your mom about getting a new healthcare provider, particularly a new gynecologist. It isn't recommended to have your own family member be your doctor, for several reasons, and in this case it worries me that her machine isn't working so you're experiencing a delay in getting checked and proper treatment. Plus, you seem to be hesitant to open up to her fully about your sex life, and to get proper OBGYN care you have to be transparent about it.
I'm linking a page from the American Medical Association explaining this, so you can have a more detailed explanation (and might be useful in case your mom gives any pushback, to explain it isn't personal):Treating Self or Family
To address your second question, we can definitely talk through ways of dealing with it. May I ask, how do you think you already disappointed your parents--was it with something similar (regarding your sex life) or something else? And have you had a conversation with them about that or about your current concerns? Often, we are afraid of disappointing our parents because we assume they would be disappointed by [x] or [y], but in reality they would be more understanding than we think.