Have you discussed this with your doctor? I would hope he would help you taper down on this......
Speed wd is much easier than opiates to get over.
You need sleep, and food. My best suggestion would be to take a Friday off work and Monday. Give yourself 3 days to do nothing but sleep and you should be feeling much better.
I was on adderall, dexedrine and meth for 15 years. I've detoxed no short of 50 times over those years. Every time its the same thing... Sleep - Food.
Good luck