Amitriptyline

I have been taking all sorts of pain killers for my Spondylosis and Sciatica but recently the doctor at the hospital said it would help with the pain to take Amitriptyline starting at 10mg. I've only been taking it a week but have found that its been making me down and quite when i'm normally a happy smiling person even with the pain. Also feeling sick and dizzy. I have also found that I seem to want food all the time which is quite annoying as I have been told to lose weight to help with the pain and have been trying really hard to diet as I can't exercise. I was wondering on other peoples experiences with Amitriptyline. If it's worth it or not?