Confusion about medicine usage. Paxonil?

Hello Doctors, 2 months back i had take some bhang after that i got panic attack and anxiety thereafter. I've consulted with a psychiatrist and he prescribed me Paxonil plus and latet Paxonil 25 mg and told me to take this meds, And that i have to take them for atleast 3 months . 2 months passed and i am feeling much better now and when i again consulted that doctor he said me that i have to take the meds for minimum 6 months. Then i asked him remedies for side effects(weight gain,sleepiness) ,then he changed the medicine to Setral 100 and told me to continue it for 4 months and there will be less side effects then before. Does it really take 6 months to stop those meds? Does setral better than paxonil?