How long does it take you to withdraw from paroxetine?

Depends. Some people, for reasons that are not clear, are more sensitive to changes in serotonergic medications such as paroxetine (paxil) and suffer from discontinuation symptoms. In my experience, the way to manage this is to very slowly taper off the medication. Depending on the dose and duration of treatment, that can take many months (and often a lot of tab splitting and quartering).