Now that is exactly what I do too. I think you could check out the DSM IV definition of AD/HD. You could also try any of the online questionnaires.

However, the only way to be sure is to get professional testing done. The doc will not only assess whether you have ADHD but he will also try to ascertain whether any comorbidities are involved.

Remember that it pays big dividends to be well informed. So read up on it as much as you can.