What is this thing dangling from my gums?

For most of today I’ve felt this thing dangling off, or near, the extraction site of my top right wisdom tooth. It feels kinda hard and the black blob of blood moves around. It’s attached to my mouth by what seems to me to possibly be a stitch that hasn’t dissolved yet?

For reference, I had surgery exactly a week ago. But I spent the night in emergency spitting out a mouthful of blood every 10 mins or so a couple nights ago, so I’m a bit wary of pulling or tugging on things, even though this is the top right and the bleeding area was the bottom left.

Here’s the picture:

https://ibb.co/q95y0Sf