I think you may be confusing friend network and business network. After 10 years in the field, it is inacceptable that you don't have at least a dozen of past colleagues to call to get an internal referral. I personally don't use Facebook but it doesn't strike me as the best platform for that. Your buddies and college friends are one thing, your ex coworkers/reports/managers are another.

TBH, it should be easy to find a gig simply by applying to open positions that you find on interesting companies websites. However, I strongly recommend that you start working more seriously on your professional network in the future. Make sure you keep in touch with good colleagues, make sure you remain in good terms with everybody, etc.