Why whatsapp deleted all my stickers?

Suddenly, out of nowhere whatsapp deleted all my stickers, including the ones in favorite. I did nothing different than i do every day. The only thing that might be kinda of weird is that i get the message that i need to free 100mb (because i aint got much memory left) but i always get it and sometimes it dissapears because i delete some stuff. But this time, its been a while since i deleted anything and the other day i just woke up and found out they got deleted (stickers).

Was it maybe my phone trying to release some space? Thats the only thing i can think of but if it did, i did not give any permission to that.

Why did it happened and how can i get them back? i tried upgrading the app but that didnt work. Thank you