I can’t move safari tabs.

I was doing school work and did the split screen so I had Wikipedia on one side and powerpoint on the other. I had finished and was trying to put the Wikipedia tab back on my other screen because I have done that before with these exact same tabs, but only now, it was not working. So I had to copy the link and paste it in a starter page. When I did that I tried moving it next to my PowerPoint tab but it wouldn’t move. In fact, none of my tabs would move. And when I go into the thing where you can see all the tabs, I can’t go into any of them. And sometimes when I try to, the screen bit that shows you what the tab looks like when you are in the tab disappears but the words at the bottom telling you what the tab is is still there but faded. Now I have had to stop doing school work to tell you guys this. Please help me. I need help. 😞😞😞😔😔😔