There are special electrical boxes made for hanging fans, which have extra support brackets. Maybe this isn't one of them.

Are you able to view the fixture from above? Attic or similar.

I recommend that you remove the fan in order to determine if the ceiling box was the proper type and was installed correctly for a fan. If you post pictures of what you find, someone may be able to offer more help than a guess.

The old steel ceiling boxes might be strong enough to hold a fan, since they usually had a metal bracket that bridged the joists, but that weight was not what they were designed for. You need to find out what has let loose, and I expect the fix will be to install a modern ceiling box that is designed to support a fan.

Bruce

It's tough to be sure from the photo, but it looks like that might be part of the box showing as it's being pulled loose by the fan's weight and vibration. If so, that's not really a safe situation. The fan needs to come down and a proper fan rated box installed. Until you can either get it checked or drop the fan yourself, don't stand under it, and keep kids and pets away too.

For sure needs to be checked into. The fan may be in danger of falling or it could be something as simple as the canopy/ covering having come loose and slipped down.

That circle on the ceiling--probably the dirty or rusty ghost print of an old light fixture that has bled thru the paint. I would cover with 2 coats of shellac (Zinsser's BIN in the red can--also available in a spray can), allowing to dry between coats & then touch up with your ceiling paint.

I would have a licensed electrician check it asap, before it does fall down on top of someone. A ceiling fan is very heavy, and that one looks like it could fall any minute.

Thank you all so much for the input! I’ll take it down and let you all know what happens from there!

Shana, I've got the same issue. How did you fix?