This happens when one of the imports is corrupt. Figure out which import you've added recently when this occured, remove that import and see if everything goes back to it's original file size.
If an import is corrupt this can also be due to it's file path being incorrect. Take note of that.
It's rather simple to see which file is causing it. But it'll take a long time if you don't know which files you've added when this occured. You would have to go through every single one of them one by one, removing them one by one, restarting the editor again and again.... It's a pain in the ass but it's easy to recover from such a mistake if you know which files are causing it.
I hope this helps.