Despite Popular Opinion...I'm Not a Fuck-Up

I know people don't really think this way of me.. but sometimes I wonder. I have basically felt this way most of my life. That I was underachieving. I can look back at all the different points in my life, especially all through school and see it right away. All my report cards said the same thing. "Could do better" and "If he applied himself". It was a toss up between if I was lazy or just not trying. I frustrated my parents endlessly with homework and assignments, because they knew I was smart. I have no problem remembering things that seem trivial ( to some people). Stuff about movies, tv shows, baseball statistics, comics, antique cars.
Focusing on the task at hand has always seemed to be a problem for me. Much of my working life has been the same. I have always managed to hold down a job for the most part. But I have never really been successful, or progressed into management. And overall, the jobs I've had, have been boring, uninteresting and unfulfilling. For years, I have struggled to figure out where my interests lie, and to figure out what I want to be when I grow up. At my current job, I come home hating it. But I'm thankful I made it through anotehr day without flipping out or getting fired or any major mishaps. I find I have to psych myself up in the morning, and for a few minutes in the car before 8am. Often during the day, I have feelings of anxiety and being overwhelmed, and that I can't do this job. This, has many times led into depression, feeling like a failure and low self-esteem. The only thing I feel that I'm good at, is being a father. Even then there has been some major issues.
I have really been having a hard time dealing with this lately. After much debate with the Lovely One, and some online tests, she has made me realize that I probably have undiagnosed adult ADHD. It only took her three years to do this. I realize that online tests don't really make anything official, but going over everything and the various answers, I can see my whole life in the test results. It really explained a lot, and I feel better knowing there is a cause for what has been happening for my whole life. And I have started reading information on line and I attended my first support group meeting last week.The group is mainly for parents with ADHD children (our daughter Rhyme Girl), but there is also some overlap with the group. Several adults there have found out they have ADHD that hadn't been diagnosed until later in life. And also a few parents have children with ASD (Autism Spectrum Disorder) like our son, Little Man. What really amazed me was that, all these other parents were exactly the same as me, facing the same issues and problems. And the fact that I wasn't alone. I'm not sure how I am going to move on from here, but hopefully this can bring some more understanding about myself.