I'm 46 Years-old And Can Not Stay Focused Nor Finish

I'm 46 years-old and can not stay focused nor finish a task. I have been this way for many years, but have never found to a doctor, because I didn't see it as a real problem, I guess. I will start to unload the dishwasher and remember I need to switch out the laundry, so I stop and go switch out the laundry. Then while folding clothes, I realize I didn't finish unloading the dishwasher. Most of the time there's something else going on that I'm in the middle of as well. It's getting very frustrating. I do the same thing while telling a story. My friends and family tell me I'm ADD. What is the difference in ADD & ADHD and what can I do to help my situation?