zoloft, remeron, buspirone and anxiety/depression

I'm a 30yr old male. I was on Sertraline approx 10 years ago for depression and it seemed to work until a crash. For one reason or another over the years, my treatment has changed several times. It is 2011 and i have found my way back to sertraline. I am currently taking 10mg of buspirone 2x day and 15mg of mirtazapine for major depression and generalized anxiety.  I have been feeling constantly tired, apathetic and despondent. My psychiatrist prescribed a starting dose of sertraline of 50mg/day. Since starting the sertraline again i have been suffering from physiological anxiety symptoms such as a tight throat, lump in throat, trouble swallowing and breathing, etc.

Is there an existing drug interaction between Sertraline and Buspirone and/or Mirtazapine  ?  Or can a person's toleration of a drug change over time?

I am also dependent on imovane/zopiclone to be able to sleep.  

Anybody?

[greenlydia]

I would strongly urge you to speak with your psychiatrist or a pharmacist to determine if your symptoms are due to an interaction of the medications you're on. Please do this ASAP as some interactions can be fatal. If you are having severe difficulty breathing, have someone drive you to the ER immediately.
I wish you the best. Let us know how you're doing.
Peace
Greenlydia