Welcome to Android Central! Which phone? How did you accidentally delete your contacts? From within the Contacts app, or are you saying you actually deleted the Contacts app?
If you deleted the contacts themselves, were they associated with your Google account, or with the Phone account? If they were associated with your Google account, then hopefully the delete action didn't sync with your Google account already--go to your Google Contacts on the web and see if they're still there. If the contacts were associated with the Phone account, then did you ever back them up using some kind of 3rd party backup or sync program?