I have almost the exact same story. I was diagnosed in May (yes in the middle of the pandemic), at 46.
My epiphany came in January, after reading ADHD articles in hopes of helping my son (diagnosed 2 years ago), thinking my childhood and his are very similar. The genetic link caused me to seek out testing to see if I was affected (this appears to be a common story amongst those diagnosed as adults).
When you and I were kids, ADHD was even more misunderstood than it is now, and the fact that you were not diagnosed as a kid is not a sign you aren’t negatively affected.
I did very well in school, but I suffered from high anxiety (also not treated very well). So without a “learning disability” I was overlooked.
Here in Canada, I was able to find a psychologist who would do the testing, and relay the results to a general practitioner who specializes in adult ADD.
I believe you, and I think you already know too. Getting the diagnosis will help, getting medication, if you need it, will help. But your GP does not understand ADHD (at least in adults), if they say you can’t have it if you went undiagnosed as a child.
I can’t recommend any particular practitioner, but I would recommend seeking out a psychologist who can diagnose ADD in adults, and have them recommend a doctor for medical treatment, and counselling for the rest. Again, for me, this was done remotely via video conference appointments, so the restrictions on social distancing should not be a factor.
I believe ADDitude has resources to be able to help you locate someone local, and another resource that might be useful to you is