Why are all my teeth breaking and falling out and rotting ? And what can I do to prevent this?

It is great that you are in recovery and a FORMER drug user.  However, damage done to teeth won't heal spontaneously, so it is likely that much repair work is needed.  Sometimes it is too late by the time a dentist can help and dentures/implants need to be considered.Seek the advice of your dentist to see what your options are at this point.

Congratulations on your recovery! Drug usage of street and medical varieties are often very hard on your teeth. Past usage may have  weakened or started decay that is now continuing the breakdown. It is best to get evaluated so that these fires can be attended to and you can start rebuilding what was lost.Good Luck--Dr Merrill