No you didn't do anything wrong.......just a series of wraps that came undone.

any archery shop should have you back up and shooting in 5 minutes. Provided they can squeeze you in with their workload at this time of the year. NOW is the time when EVERYONE hands them a bow and says "Fix this".
So don't be surprised if they tell you to come back in a day or 2 for a 5 minute fix.

You COULD do it yourself but you'd obviously need the serving thread, bowpress and the knowledge of how to use both.