From what I know (having taken many different SSRI and learning as much as possible about them all) is that what you are experiancing can happen with SSRI's Often the dosage needs to be increased and/or a second anti-depressant may be added. Common practice these days are that medical professionals are no longer just using mono-therapy; in your case Paxil by itself. Another problem may be that you have plateaued at your current dose. This too is common for many and dosages need to be reviewed with you and your physician.
I hope this helps somewhat.