Take 4 Omega 3 fish oil supplements*, daily: (certified free of mercury) it is best if consumed with an antioxidant, such as an orange, or grapefruit, or their FRESHLY SQUEEZED juice. If vitamin E is added, it should be certified as being 100% from natural sources, or it may be synthetic: avoid it.

Alternatively, you could go to the searchbar at http://www.mercola.com and enter: "krill oil". While you are there, enter "nutritional type", and eat more in accordance with yours. Exercise moderately, for 30 - 60 mns, daily.

Avoid any powerful, addictive central nervous system stimulants which may be offered! See http://www.drugs.com & http://www.rxlist.com on medications.
References :

I wouldn't go into your doctor and tell her that you "suspect ADHD." For some reason, doctors don't like spending twelve years learning medicine only to have people come in with a diagnosis all picked out already, and depending on your doctor that can really affect your experience. It would probably be better for you to just go see the doctor and " They might refer you to a psychiatrist, they might prescribe you something themselves, or they might blow you off entirely…adult ADHD is still a relatively new concept in medicine. Don't be afraid to seek out a second opinion if you feel the need to.

There are non-medical things that you can do to manage your symptoms if you are diagnosed. For instance, when I study I generally have the material for several subjects within arms reach and if I notice that my attention is waning I switch to another subject for awhile. I also find that putting unobtrusive music on or even switching on TV guide channel helps; anything that creates background noise but isn't interesting enough to distract you. Also, strange as it sounds, when I really need to focus on something for a short period of time (like for exams), I count to myself while I'm thinking about whatever it is I need to be thinking about. People who don't have ADHD find this unfathomable, but it works for me. The drugs WILL help you focus, but there are side-effects such as dizziness and insomnia, and forget about caffeine while you're taking them…better to try other coping strategies before turning to pharmaceuticals.

Long story short, go to the doctor and explain your issues honestly if you feel the need to, but don't just go get treated/evaluated for its own sake. If you've been managing this far and it isn't a big burden on your life, don't stress it.
References :
Nursing student / ADHD "sufferer"