Much depends on your background. Have you been riding for 10 weeks or 10 months or 10 years? Did you do at least two rides of 80% of the distance (80 miles) prior to your century? Are you relatively fit, healthy, and active?
A good rule of thumb is one day for each hour of your event.
Of course, you could have a little bout of post-ride depression. This is common, especially since this was a big goal for you and it's late in the season. If you think this might be the case, my advice is to pick another goal (cycling or otherwise) and start working toward that.
Congratulations on your accomplishment!