It sounds worth investigating ! Do you have an adult you trust who you could ask to take you to a mental health professional? You don’t necessarily have to tell them you think you have ADD if you’re not comfortable; you could say you want help dealing with the stress of a demanding school regimen and your friend learned a lot of stress management techniques by going. Then you could share with the professional your concerns.
You could also talk to a counselor or guidance counselor at school.
I don’t think you should have to deal with this alone, and I don’t think you should wait to get help with whatever you’re dealing with!