Google updated their webmaster tools console design recently, perhaps you are misreading it/looking at the wrong thing.

Either you are looking at the wrong thing, or you have found out really bad news. Sometimes it is easy to mistake internal and external links in WM tools. If you notice a significant dip in backlinks, check your indexing and make sure your site is indexed correctly. Also you might want to check back with WM tools in a few days just in case it was a bad day for their stats.

Google has more than one database and routes to get to them. And, depending on the route taken the data could differ. Not to worry. Nothing happened.

This is the same thing that happens when you do a search. You can search 4 or 5 times a day 9or even in an hour) for the same search term and it will display a different total number of pages indexed; sometimes differing by hundreds of thousands. Next time you go back and search again, there they are again.

I have a desktop program that monitors backlinks and it's never the same from one day to the next. It goes up then down like a yoyo. Just take the average (or what you see the most) and you'll be OK.

Bottom line... is you site ranked well? That's the proof of the pudding.