Help! Once again my Illustrator is erasing stuff from my artwork and undoing things I've done before

Hello everyone, my name is Sofia and i'm an Illustrator from Portugal and i've been experiencing some strange things with my Illustrator and Adobe Acrobat! 

In my illustrator artwork (file) elements from my artwork have been missing or disappearing and little things have been changed, like for instance, the last thing i've noticed was the texture i've done myself on a tree, round half circles, once again, done handly by me without creating any texture per say and when i opened the file to continue working they (this time) weren't actually missing but the color was blue instead of dark green, what i mean is, they went back to the color they were before i started painting them. My Acrobat is showing in one particular work way too much vivid colors, colors that are way too much vivid then in my actual Illustrator artwork, did i saved it wrong on the Pdf i've generated? I don't know and last but not least, when i take screenshots in my new Macbook Pro Max M3 computer the colors when uploaded to my website on Cargo Collective seem dull and fainted, can someone explain to me why too?

Thank you for your attention! 

Hopefully this will end soon because it's my work that's at risk.