We seem to share similar problems.
I will echo all that Patrick has said and urge you not to skip that medical appointment. You may need to see several different specialists (and they all may not agree).
There are other options that may help such as medical disposable anal plugs to help avoid a BM during a social engagement.
I have carefully used enemas for years to manage my fecal incontinence.
An empty colon cannot have a bowel accident. I now use a medically-prescribed enema system.Kegel exercises may help but are best if you are properly instructed. They may enable you to delay defecation long enough to find a toilet.
You will need to be patient and experiment to find what works best for you.
Feel free to ask any questions or to PM me if the subject becomes too personal to post in public.
--John
(double incontinent)