First of all, don't get down because of it, and most of all don't let someone's opinion be your reality.
Keep your file up to date, add your hours every month, this shows that you are still interested. Your time till you can apply again depends on which day of your process you were not successful. If you only did the first day and failed the sim you have to wait one year but I heard if you made it through the third day and failed, you have to wait 3 years....no matter how long you have to wait......if you really want it than you will get it. don't give up and keep your goal always ahead of you.
Wish the best for you.