How common in serotonin syndrome?

I am a bit of a hypochondriac who suffers from severe depression. I was taking 40mg of paxil, 45mg of buspar and 400mg of tegretol XR. Now, my doctor has changed me to 40mg of paxil, 60mg of buspar, 50mg of amitriptyline, and 300mg of tegretol XR. My doctor is a family physician and not a psychiatrist. I've been reading stuff online and I'm getting worried.