Paragraphs randomly deleted and text boxes moved

Hey, so I'm using Acrobat for the first time for an assment that I'm working on and it's nearing its deadline and I'm having some issues that are driving me crazy.

I finished writing and answering all the questions for my assessment and was going through and proof reading it before getting ready to submit.

I noticed that somehow, some of the smaller text boxes I had, had moved up my pages and were overlapping onto my bigger text boxes. When I tried to select them to move them back to where they belong, it selected the bigger box instead. So I clicked out of the box to deselect it and somehow, that deleted the whole box. I didn't click the trash icon. And now my whole paragraph is gone. I can't undo the action, because the undo icon is grey (as in, nothing to undo). I've tried "ctrl Z" and that doesn't work either.

This has happened twice already with my smaller paragraphs that were easier enough to rewrite. But now it's happened to one of my biggest ones, that took me so long to write and now it's gone, probably forever? 

Can anyone tell me why this is happening and if there's another way to get my paragraph back?