Yes, Paxil can lose effect, but not sure it is biological, it can also be that the underlying anxiety is reactivated for new stage of life reasons, and that is what needs to be addressed, so counseling is definetly in order.
Also, the specificity of your anxiety makes it even more important that you try to understand the why's and don't overly rely on medication.
The maximum dose issue is not a real issue. These are different drugs,and people respond differently to different doses, so try the lower dose, it will probably be enough, especially if you have counseling as well.
hey3