ADHD at any age is stressful and challenging. With ADHD, life is inevitably difficult, and the rammifications can be felt in all domains: work, school, relationships, finances, and the home. There is considerable stigma, as people with ADHD are accused of being "lazy, flaky, disorganized, and forgetful."
The one advantage to being an adult is the access to choices and help. Kids rely on their parents, teachers, and counselors for assistance, but as adults we are more empowered to seek out medical care, classes, and information.
The first step is to get a diagnosis. Seek out a doctor or behavioral therapist who specializes in ADHD. From there, you can determine what type of treatment to explore, whether it be medication, behavioral therapy, diet modifications, or a combination of both. And reaching out to online communities such as these is a great support too!