Why can’t I feel any benzo’s after almost a year of stopping them

Apologies if asking this here isn’t alout l.I’ve looked everywhere and can’t find an answer to this or anyone who experienced this.

My last time taking a benzo was about 300 days ago when I was taking a very high amounts of Xanax daily for 6 months and ended up rapidly tapering off. Since then I haven’t felt any prolonged withdrawal symptoms or any kind of withdrawal. I took 30mg of Valium yesterday and felt absolutely nothing, yet I have no tolerance. How is that possible?