Saved comments have disappeared

The comments that I made on a document are all gone. I know that I certainly saved them, I always save my changes. Even if I had forgotten, that little message would have popped up, warning that there were unsaved changes, and then I would have saved the changes. But now they're all gone. There are three versions of the same document now (and I have not intentionally duplicated them), all slightly different sizes (69 KB, 73 KB, and 76 KB), which seems to suggest there’s some difference in the contents they’re holding, yet none of them have my comments. I originally saved the document as a PDF to Downloads, the uploaded it to Adobe Acrobat, made my comments, saved it. I don’t believe I made all the annotations in one sitting either. Or, if I did, I definitely opened the document after I finished annotating and the comments were still there. I checked my File Explorer Downloads to see if there was a previous version and there was not, but there is not. The date of last modification on Acrobat is the same as when I was last working on the document and when I finished with my comments/annotations. The document isn't shared with anyone and I’ve been working on it from the same device. I haven’t done any update to Acrobat since working on it. I did just do a Windows update, though I don’t think that could affect the file. Is there anything I can do to retrieve them from whatever void they’ve disappeared into? 
 

Thank you!