Posting a followup to this.
Eric @ Lighthouse linked to above administered a TOVA test and thorough questionnaire to me and gave me my official diagnosis 2 years ago.
However, he can't prescribe the medication and he referred me to Dr. Donna at Medconsult who set me up with a Ritalin prescription. To say that it has been life changing (in a positive way) would be an understatement.