Taking zolfesh and mirtaz
once in a fortnight is not addiction and it is generally not a right way of taking treatment. I understand that you are having trouble going to sleep.
Before you start yourself on medication, you should try all the sleep hygiene
measures. Firstly stop all tea/coffee/alcohol/chocolates/colas as all of them contain caffeine. Next you should start with daily exercise for 45 min to 1 hr. Take a warm bath at night, regularize your sleeping timings. Dont try too hard to go to sleep. If you are not getting sleep, sit up, do some reading and again go to the bed when you feel drowsy. Use your bed exclusively for sleeping and keep your bedroom lit dim. If the problem still persists, please visit some other psychiatrist
who can help you.
Hope I am able to solve your concerns.
Have a nice day.