Advice needed

Hi everyone. I haven’t been on here in forever. Anyways, I need some serious advice. I’ve been dealing with social anxiety for a while and it’s really never gotten in the way of school and academics. But recently, I’ve been so stressed that i’m having panic attacks in the morning before school and in class too. I’ve talked to my parents about it but they just think that i’m shy and don’t have an anxiety disorder. I want to switch to online school next year to be able to focus more on school, but I don’t know how to tell them this without them getting mad at me for “pretending” to have a mental illness. Thanks in advance for any advice.