Paxidep is the brand name. It contains a medicine called paroxetine. It has some very severe side effects including sleepiness. On withdrawal it causes all sorts of problems including loss of sleep. You should not worry since in due course such withdrawal symptoms will disappear.
It might interest you to know that paroxetine is under investigation in advanced countries because one of its side effects (which was intentionally not disclosed by the manufacturer) was tendency on the part of patients to commit suicide. It is good that you have stopped this dangerous medicine.