perscription diet pills

I have not taken a diet pill in 2 months, I had tapered down to a quarter of a pill (didrex )and then stopped due to a nervous feeling and shakyness. Now without the diet pill I cant sleep well and developed a feeling of shakyness and panicy at times and at times depressed. I will not take this pill anymore but it is amphetamine family and I need to know if what I am experiencing will pass . anyone stopping amphetamine , diet pill successfully . What frightens me the most is that what Ive read about cesation of the drug after long term use, mental depression and could it be temporary or permanent. For many years I took this pill first for weight loss and then because it offered me a clarity and alertness I was so used to from taking it. I am in full blown menopause and am very symptomatic from that. I never took more than 1 pill a day and sometimes i would take a half. I read that this drug can also be used to treat depression. Will these symptoms pass or has my brain chemistry changed.