Fluoxetine or Sertraline or Mirtazapine.

I have Generalised Anxiety disorder and Hypocondriasis ( Health Anxiety )since last 12 years. I started my treatment with Paroxetene 25 and Clonazepam 0.25 and took it for 1 month but it lead a bery bad constipation. My doctor shifted me to Escitalopram 10 and Clonazepam 0.25 for next 9 yrs, I took it. Then I was put on Vortioxetine, Desvenlafaxine, Bupropion, all gave me really bad constipation. At last a different psychiatrist put me on Vilazodone for 3 yrs and it doesnt cause me any constipation, but it was not effective in managing my Anxiety disorder and racing thouhgts. I was then shifted to Sertraline but it also caused constipation. Now my doctor has prescribed me Fluoxetine 40 in the morning and Mirtazapine 15 at night. I have started taking it but mirtazapine is causing very much sleepiness. Can sum1 please advise me does fluoxetine cause less constipation, than other SSRI and SNRI and can I skip Mirtaz due to excess sleep. And continue clonazepam 0.25 as I did for 12 years.