No it would not affect your nerves, the nerve terminals simply refer to the source of where the norepinephrine and dopamine are released. It does not relate in any way to your nerves. If the medication is working and you feel fine, I wouldn't be too concerned. If however you're still uneasy about the effect you're feeling, by all means contact your doctor.
Should I discuss this with my Dr? You said it effects the nerve terminals, since I am normal nervous, irratatible and jumpy would it help to have some kind of "nerve medicine" to take after I finish the Adipex?
Though rare, euphoria can be a side effect of Adipex-P® (Phentermine). Similar to amphetamines, phentermine increases the release of norepinephrine and dopamine from nerve terminals that can cause the “calming effect” you're describing. It could also simply just be that you're feeling better with the weight loss and therefore in a better mood.