Do I have horrible vision? PLEASE HELP ME!!!?

Recently my eye doctor said the my vision was 3 to 400. Is this equal to 20/2666.66 Snellen? He said flat out to my face the my vision is horrible. The only thing is that he didn't tell me what it means. This is driving me crazy because I am VERY pionate about aviation and I am starting my pilot training next year. Now I am worried that my vision by no longer be correctable to 20/20 Snellen. So, if there are any optometrists out there, PLEASE HELP ME OUT!!!!