I just had a game where my opponent played psychic scream (which may or may not be related to the issue) and on the following turn I did not draw a card. The rest of the cards moved over in my hand as if to make space for a new card, but no card was drawn. I played my turn without it, and on the following turn I once again did not draw a card but I also now could not play any cards in my hand or make any attacks or other actions, forcing me to concede.
A known issue. See for example:
Note that there was a small patch today with no release notes, so it might have fixed some recent issues like this one, who knows. If you encounter this issue again, you can force-quit Hearthstone (Alt+F4 in Windows) and restart it right away to return to the game in progress and clear the invisible card (though future draws might still have the same problem).