First, sit down and breathe. The absolute WORST thing you can do is call in sick. Sit down and write down all your good qualities and all the good things you do to make the company function. Memorize them. Look over your closet. If you have nothing professional to wear, break out the credit card and go shopping for something that looks like the job you WANT to have. RIGHT?
YOU CAN DO IT!! MOST IMPORTANTLY, AND I CAN NOT STRESS THIS ENOUGH, DO NOT, AND I AM SERIOUS HERE BECAUSE I HAVE BEEN IN YOUR SITUATION MORE THAN ONCE, DO NOT DRINK AT ALL THE NIGHT BEFORE.
After the day is over, go ahead and treat your self but DO NOT DO IT THE NIGHT BEFORE. I KNOW THIS FROM EXPERIENCE. I AM 59 AND GOING ON 60. TRUST ME. GOOD LUCK!!!!!!:ghug3