Answer:
Yes, there are online evaluations on the Internet to screen for ADHD. The most reliable one is the Jasper/Goldberg Adult ADHD Questionnaire. You should not take the advice of an online test above a doctor's diagnosis, however, printing out the questionnaire and taking it with you to the doctors office may help a great deal. Whether you choose to avail yourself of the online questionnaire, if you suspect that you have ADHD you should consult your doctor.
If your doctor says he/she does not "believe" in ADHD, ask for a referral to a mental health practitioner.
Lastly, many mental health disorders and conditions present themselves as ADHD in a screening test. A psychiatrist or psychologist can sort out whether or not you have ADHD, depression, OCD or any one of a number of disorders that are related.
Good luck with your quest, if you do have ADHD ... welcome to the "IN" crowd.