@crazyydudee,
based on this post :
http://able2know.org/topic/227663-1#post-5504497
This problem you've stated here started a while ago. This issue reflects the same problem you've been having all along - your neediness PLUS her inability give a consistent message about how she feels. How you state that she acts seems that she is not a mature adult. Pardon my bluntness, but you seem immature too.
I'd say from your own telling of your story... that the two of you are unsuitable as a compatible couple. Why not either take a break or stop seeing one another. Find a way to keep your emotions centered and keep your personal integrity (no begging, pleading...etc.) Stand on your own two feet.
Lastly, exam times is clearly not a good time for you to see one another and carry on a committed intense relationship. If you can't find a way to back off, perhaps you need to re-think things.