Get off TSR, and revise. Just revise all the time. Yes it is very realistic. If you get your head down, lose a social life and revise.
Why are you giving me a thumbs down? Perhaps the answer you wanted was of course you can do it, chill out relax go to the pub! Once you get in that exam hall all the answers will come to you. I am only speaking from experience, if I had revised more I would have got three As!