As someone who also had a high GPA lower MCAT, all I can say is...don't give up! This was my 1st year applying and I got into 3 schools, and waitlisted to a 4th! Please please please don't let a few harsh words deter you from pursuing medicine if it is really what you want to do. Instead, use it as encouragement to do better on the next MCAT. Look, an 18 is low...bottom line. BUT people have gotten in with such scores.
I am not sure how far in the application process you are, but if I was you I would really try and improve my score to even a 20. Every point helps. Your GPA will be a good cushion for your lower MCAT score, and Adcom will see that. Apply for 2005, and until then build your clinical experience. SHADOW A DO!
And since you have some time til applications begin, call schools you are interested in, and speak to their Admissions Dept. Tell them your story, and ask them what you should do. I mean, who better to guide you then the schools themselves? Besides that will give them time to get to know you and your interest in their program.
It is going to be a rough, frustrating road but don't let it get you down. Make full use of whatever utilities are out there...MCAT prep, shadowing, SDN. Good luck.