Visitor Visa - B2

Hello,
I am a 30 yr old medical graduate and currently a 2nd yr post graduate student.
I wanted to go to USA for an observership but my visa was rejected.
I have already given usmle step1 and cs.
My interview went something like this:-
VO-What is the purpose of your visit
Me-I have an observership in June
VO-what do you do?
Me-I am a second yr PG student in India
VO-so are you going for clerkship?
Me-No, observership (the letter I had stated that I will be observing the physician)
VO-started typing something(shaking her head)
VO-it is a clerkship.
Me-no an observership
VO-you are a graduate?
Me- yes, I am a graduate but doing my post-graduation.
VO-went for 2 minutes
then she came back again started typing something while shaking her head
VO-Sorry, you don'y qualify this time. You can't be a medical student to do observership.

Now, as far as I know a medical student as well as graduate can do observership but only a medical student can do clerkship. I am not eligible to do clerkship since I have already graduated from medical school and American medical colleges don't accept Indian post graduate students as medical students so technically I am not eligible for clerkship.

So, after this incident I am shook. I have no other reason right now to apply and just want to ask when should I reapply? Should I reapply with the same reason again?

Any help will be much appreciated. Thank you.