Hi there,
Have courage my friend.600 is not a bad score. it depends entirely on your profile is and what you aim to do and what you have done. Schools will generally look at your entire profile before deciding your candidature. GMAT is not the only decider there. If you can project your strengths effectively, negate your "supposed" GMAT weakness and offer a lot more to a prospective class and professors and to the school as a valuable future alum then you will be in good stead.
When I took my GMAT the first time i scored a 550. I was devastated. My background--I have a masters degree in Computer Science, a bachelor's in Computer Engineering and about 9 yrs work experience..a lot of which is international experience. I have extensive background working in government and Non government entities leveraging technologies. I also belong to a highly competitive demographic group. Long story short, I applied to Chicago Booth, Kellogg and DePaul since I wanted to be in the Chicago area only. I was rejected at both top schools. I did not give up and studied again for the GMAT and after 3 months of practice i landed with a score of 600. Again not your "supposed" range for either Booth or kellogg. But this time I wrote essays that demonstrated my strengths, things I had done, a clear path towards my goals and how I saw the schools help me achieve my goals. I clearly listed out how my education and experiences enrich my work, community and organization. I very clearly explained my strengths during the interview process. Well again long story short...I got accepted to Booth and Kellogg. I went with Kellogg since I felt my goals were better served by the education experience at Kellogg. I feel Schools dont necessary look for GMAT superstars. They look for people who have diverse experiences, good previous academics, a history of positive work experiences and very lucid thought process. You need to be able to offer the school something no one else does...It does help that you get a good gmat score but a very high gmat is no guarantee for success. It doesnt take extra-ordinary people to do extra-ordinary things..focus on your strengths, list out what makes you tick, what you are passionate about, what makes you get up in the morning and what makes you stay up at night. Again this is very individualistic and what I say may not apply to everyone..I had a good academic background, fantastic work experience, wrote essays that were from the heart,connected well with the schools to understand them and put that out in my application. Dont let GMAT be your be all and end all.Be yourself and prepare for success and failure and not let either affect your thought process. Success belongs to those who want it most. Best Wishes !