Sudden loss of impressions

Hi, I hope someone can help me.

I had a post on twitter that had over 4500 impressions as of yesterday. I checked my analytics this morning only to find that the post had now dropped to around 600! I have never paid for followers or impressions so I don't understand the sudden loss. The post was a link to an article on a website.

I have to report my results to the board of directors, and now a huge chunk of what I had gained over the past month has been lost.

Please help!

Poster :