Some of my credits disappeared

I just lost 19K credits, I have it on video.

So now my ballance is switching between $18450 and $18550 without any purchases or sales.

Edit: This was probably the hourly tick up. my mistake.

My "Net Worth" was more than ~19K when I logged out before the wipe and when I started with this wipe I had ~9K.

Thank you for the help in advance, you guys are great.