I'm so sorry to hear that, phenibut is a really dangerous drug to get addicted to
It's a Soviet medication for anti-anxiety and prescribed in Eastern Europe. Somewhat similar to Xanax except it agonizes a different GABA receptor
The effects can be described as all the positives of alcohol and Xanax with none of the negatives. Lower anxiety, higher sociability, euphoria, heightened senses, but you don't risk blacking out or losing major control of your motor skills
The withdrawals however, are severe and can be fatal