I just wanted to know can overactive bladder be a sign of something more serious?

Here are some ...: "Pure" OAB would not generate serious threat to life, but some unclear disorders from regional nerves, joints, muscles, the pelvis, lower part of body may be the underlying reason to cause symptoms similar to those from OAB; thereby, chronic pelvic pain syndrome (CPPS) has been coined & used. So, seek professional evaluation & counseling before assuming something leading to unnecessary anxiety.