Getting my ADHD (?) diagnosed

First of all, I am not certain I have ADHD. I do recognize myself in a lot of attitudes, hardships and little things, and it's impacted my life for too long now.

I can't afford to go on like this anymore. Who should I go to? How long does it take for me to recieve a diagnosis and how expensive will it be? If I'll have to take meds, for how long and how expensive are they in your experience?

Thank you all in advance