Embarrassing tech question re embedding video links

Hi, This is embarrassing to even ask. Whenever I embed a link in a post, it leaves a ton of extra space because the preview of the post shows that a videoclip is also included below the link.  The published post itself doesn't show the clip and only shows the link but the post has tons of space below. I seem to be the only one doing this and wanted to see if anyone has tips for how to prevent all that extra space.