How do I undo my work when I come back to it?

Ziyad EN Basic Posts: 1 New Here
edited October 30 in Ask the Community

I was making a mind map for a health assignment on Nutrition, but I closed my computer (not the tab) to take a break for little while. When I came back, I tried working on it again but I accidentally deleted pretty much half of it. Then, for some reason, the website told me to refresh the page due to a problem that "they were working on solving". I couldn't close this pop-up so I had no choice but to refresh my page. HERE'S THE PROBLEM, when I tried to undo the mistake I made, it wouldn't let me. There was no option to undo it. So my question is how do I undo past work; like checking the version history in a Google Doc?