Whether or not you have ADD can only be determined between you and a professional qualifed to diagnose ADD/ ADHD.
While the symptoms you list *could* be associated with ADD, the diagnosis would require, among other things, a history of such difficulties along with other defining characteristics.
I do have ADHD and, unfortunately, the condition is over-diagnosed and inappropriately diagnosed. It has become a catch-all category making many of the "diagnoses" unreliable and, as a result, detracts from the credibility of the condition and the difficulties associated with it.
Does this mean you do not have ADD?
That is not what I am saying.
Like Catfish said, there are other conditions/ circumstances/ experiences that can cause sypmtoms similar to those associated with ADD/ ADHD.
But whether it is ADD or from some other cause, you still have a problem.... namely, that you are having concentration difficulties and you are inadvertantly over-looking things or you are distracted.
Perhaps researching various strategies that those with similar difficulties employ to help them better manage such symptoms will be of benefit to you.
Not every strategy works for every person, so review several and then pick and choose what works for you. Or create your own strategy from the various aspects of the strategies you discover. What will work for you is as individual as you are.
Be gentle and kind with yourself.
Acceptance on someone else's terms is worse than rejection.