I think there's some confusion here. If looping a script (repeating an element of it over and over until a condition is met) is really want you want to do, then you might have a look into something like 'while', 'until', or 'for'. See here (half way down) for more info:
If you want to repeat the whole script at certain times (which is what it seems like based on what you say the script is doing), then something like 'cron' or some other scheduler might be the way to go. The 'done' statement just ends a 'do' statement (often in conjunction with a loop):
Perhaps a more specific example of your script and / or what you want to do with it would be helpful.
while <condition>; do <something>; done