Is it common for your gums in mouth to be attached a tooth that is just hanging there?

No, It is not common for gums to be attached to a loose tooth. When a tooth becomes loose, it means that the periodontal ligament attaching the tooth to the jawbone has been compromised.

If you have a loose tooth, it's essential to consult a dentist or periodontist as soon as possible to determine the cause, rule out underlying conditions, and determine the best treatment course.