Long-term damage after 1 year of intermittent Phenibut use possible?

Greetings, I'm wondering if the symptoms I'm currently experiencing could be due to Phenibut or something unrelated.

I started taking Phenibut April 2020, never went above 1g, never took it more than once weekly. Usual dose was between 500-750mg.

I also took a break from it for a few months at a time, but also used it for about 5 months continously, once per week. In total, I used it for 15 months.

After the last dose of Phenibut 2 weeks ago, I experienced Anxiety, depressed mood and subsequent anhedonia / emotional numbness, 2 days after dosing, didn't take it since. Took about 850mg that time, and the emotional numbness still persists after 2 weeks.

I have however taken this amount before to no ill effect, at most I'd feel a little numb / anxious for a few days at most. Never this intense or long though.

Could it be that using it on and off for 1 year triggered some kind of sudden bad reaction? Is that even biologically possible?