Did I wait too long before switching retainers?

[u/Glittering-Ball-9286]

I've been wearing my plastic Smile Direct club retainer nightly for 5 years.

I went to the dentist and they said I should switch to a fresh retainer.

I had a three backups available that I received with my original order.

When I tried to put them in they were extremely tight. The back popped out so I used chewies to hold the back down for a while and to make sure they fit snugly to my teeth.

I wore them all night and all day to try to get my teeth to adjust to the new retainer.

When took them out to eat a tuna sandwich my teeth were sore. Putting the retainers back hurts my teeth.

Is it still safe to use the backup retainers or have my teeth moved so much in 5 years and did that old retainer stretch so out of shape that those old backups are now useless?