I need help! What shall I do?????

I am 26 years old grad student who's taking 16 credits.
It seems the courses are overloaded to me considering I have ADHD(yes I've been clinically tested by a psychologist) and besides English is my second language(Korean) But I'm doing ok in school. However, I've been sick in the past several days(viral infection) so I had hard time keeping up studying and getting highly motivated again.
But I have exams coming up soon and so I have million things to do. I'm really nervous and really really distracted keep thinking about what I should do whether I should get incomplete in one course and graduate a semester later or just finish in school earlier. I think I can pass that course and just graduate but I want to graduate with good grade since I have poor undergrad 2.9GPA.(well, I'm planning to take more undergrad courses)
What shall I do? Does incomplete in 3credits course would affect it?
I feel frustrated because I'm not a "normal" like other student who can study hard and get good grades and going through the right path traditionally.
Also I'm trying to work with physician about dealing with ADD I have been suffering since day 1. That's why I need some time this semester.
What do you guys think is the best idea?
I would appreciate if you can help with my problem. Thank you!