I am not a doctor, but it sounds to me like you have relatively weak case of, "the doubting disease". Ussually you have anxiety while sleeping or during the day about situations that "could" occur, but more than likely won't. This is called Pure OCD. I have very similar issues, and I have had them since a small child. This is what differentiates us from your average anxiety dissorder. The on-set is ussually younger than most, night terrors as a child, school anxiety, then you grow up rellatively anxiety free until real life kicks in or a major life event triggers it on again.
Good news, there are treatments available. Try CBT first and see if that doesn't help, also mindfulness meditation has been instrumental for me. If you consider drugs, beware the antidepressant becuse OCD sufferer's ussually react badly to them. A benzo could work for you, but I would exhaust all other options first such as herbs like Kava and Valerian. If you have stomach pain, try peppermint tea, it is wonderful.
Like Steve said, welcome to the club, we all have experienced various forms of anxiety. Anxiety is strange that it manifests itself in different ways for different people. For me it was always in my head. I was always overthinking everything to the point where I was getting paranoid or doubting things that I had been able to deal with before such as a bolted cabinet falling on a child. Sounds like Pure OCD.
Choosing a doctor is also viatal. You need to find someone who has a lot of experience with anxiety dissorders in general, so that he can make an accurate diagnosis. He should be able to help you through the medication selection if necessarry and also give you more accurate diescription that I have provided.
Your definitely not alone!