Doc says symptoms of bp ii(depressed in past), ill stop what i'm doing and randomly pace thinking about other things, then realize this, bp ii or add?

Not so simple.: It can require intensive teasing apart to rule in or out these diagnoses which may have overlap in symptoms.

Possibly bipolar: ADD is a hard diagnosis to make as an Adult if it was not present as a child. OCD is another possibility. Would need more information and history that can only be obtained by a trained Psychologist or Psychiatrist. Would also want to know there are no substance abuse issues and that your medical labs are normal.

It's just a behavior: I expect many will disagree, but to me it's just behavior. Either you are not very invested it the 1st activity, or the other things are more attractive to your mind. Few of us master control over our attention - it takes awareness and discipline. Also, there has to be value in the target. Before you call it pathology - ask if the 1st is important, if problems aren't churning in your head. Okay?