Thank you for writing. This is a hard way to live, I know. The difference between a “quirk” of personality and a mental illness is whether the behavior interferes with social, occupational, or daily functioning. The amount of time you are spending with examining, managing, and fixing every account to perfection probably is getting in the way of more important tasks.
Although I can’t make a diagnosis on the basis of a letter, your description of your behavior is consistent with a diagnosis of Obsessive Compulsive Disorder (OCD). OCD is an anxiety disorder. The individual with OCD falls on some behavior(S) that seem to relieve the anxiety. Often what starts as a harmless diversion takes on a life of its own. When the person gets anxious about recurring thoughts or sensations or ideas (obsessions), they come to believe that the only thing that will relieve it is to do something or some combination of things (compulsions).
Compulsions can take many forms. What you describe is a kind of “checking” behavior. You check and double check and triple check to make sure something is correct and perfect. If untreated, OCD can get progressively worse — as you have experienced.
My guess is that the obsession has something to do with perfectionism. Your answering compulsion is to try to make things as perfect as you can. Of course, “perfect” is unattainable so you get caught in a loop of overconcern about how good something is, trying to make it better, being unsatisfied, trying again to perfect it, etc.
OCD does not go away on its own. But the good news is that it is treatable. Cognitive Behavioral Therapy (CBT) has been found to be very effective. CBT is a problem focused treatment that helps you change your patterns of thinking (obsessions) and find other ways to relieve your anxiety. Sometimes some medication is also prescribed to help bring the anxiety down.
If the pandemic has limited your ability to get out to see a therapist, consider making an appointment with an online therapist.
If you can’t find a CBT therapist right away, do consider purchasing a workbook on managing OCD. There are a number of really useful workbooks available for you to use as a way to start helping yourself.
I wish you well.