It's undoing itself >:(

I am so confused and frustrated.
I was working on my skin, basing it off my other one.
So I was using the rectangle blend tool thing, and it started undoing itself until it was literally the
old skin I was basing it off of…
Also the undo button, I was trying to undo something, yet instead of undoing the
pixels I wanted undone, it skipped to the last pixel I put instead of the other, like I was putting a pocket,
and just before that I was drawing the hoodie, then when I clicked the undo button it undid the hoodie instead of the pocket.
It’s very irritating, I can barely make my skin without having to redo steps just because of this.
Am I pressing something wrong?
I’m so frustrated I just couldn’t finish my skin in the end since it kept undoing ;^:
Can someone please help?

The exact same thing happens to me it’s so annoying to spend hours on something and then it all gets removed :frowning: it seems to only be the normal body layer for me