You should probably select all of your text, copy it, and apply it to a clean, fresh Word document, text only, no formatting, and re-apply the styles as necessary. I suspect hidden formatting codes are corrupting your Word document.
Kindle inserted asterisks or stars every place where I skipped a line.
That's a new one!
How do I remove them from my ebook?
Same way you put them in, because, really, "Kindle" doesn't insert anything into your book. The Kindle conversion merely tries to make sense out of what you have uploaded.
You might search "nuclear option" on this forum. It's a way to keep the cheese while getting rid of the mold. Copy the whole thing, paste it into Notepad, then copy the clean text and paste it back into Word for proper formatting. (Word is not the best way to format an e-book, but it's the only way known to a majority of author-publishers. There are some pointers on my blog, the third post.)
Good luck! -- NJ
The book: Notjohn's Guide to E-Book Formatting (revised and updated for 2017)