Definately read First Aid. It will calm you down.
1. ROS matters a lot, and it needs to be specifically focused on the differential, not wide.
2. Exams are focused on the area of complaint, plus one level above and below. Very brief. Pleuritic chest pain... an acutely focused history, shorter ROS, very short family hx, ask about travel (PE), you know the drill....double check vitals for fever, RR, examine the chest throughly, the belly some, probably ankles for edema, JVP, focused, not everything, you are only expected to what's most pertinent while being thoroug, but not comprehensive. Just think of being practical, and problem/area focused, and any system directly connected to the problem.
2. READ FIRST AID STEP2 CS.... it tells you crucial things like what it means when a patients says shh, shh, shh when you are auscultating, or wears a mexican hat (travel exposures), to never forget to introduce yourself or drape (each one gets a point), to always auscultate and examine on bare skin (which we rarely did in hospital rounds). It's a good read, and really covers DDX ideas thoroughly, and the most common presentations.
3. CS is NOT HARD AT ALL....Time management, as First Aid says is the main thing that trips most people up. Practice your flow 4 or 5 times with a friend or at home, you'll probably feel much calmer.
4. Be really courteous to the patient. They will actually help you.
(Dont' be afraid to say, if you are blanking, "So, is there anything else you haven't told me that you feel I should know?"... they will remind you of things... just like in real life)
5. Dont' forget to ALWAYS reccomend protection for sexually active individuals, and council on smoking cessation, as needed.
Visualizing, and practicing the 15 minute encounter will probably remove your fear.