Group Tabs

Hi. I frequently keep a lot of tabs open in safari at any given time to help me remember various information or things I need to do/order later. I keep getting suggested to “group my tabs” by relevance and type to help organize them by Apple. Okay. Finally did that today…all my tabs are gone now. I made 7 different groups, moved several tabs into each one…they’re all empty…what happened? Where did they go? Why suggest this feature if it’s not going to work? I keep these tabs open for a reason. I struggle with long term memory and so I won’t even remember everything I tried to save. Which sucks. Can someone help? Am I doing it wrong? Did I just misunderstand the feature? They’re all gone.