We've been pouring central nervous system depressants down the neck for ages, so when we stop, there is a rebound effect as our machine recovers after the weight of impairment is lifted. It springs up and overshoots, and is much more reactive to small stimuli at first. It will settle down in its own time.
For help sleeping at night, look at the suggestions that help even non-recovering addicts get settled. Exercise, diet, some tryptophan (milk and cereal work for me) before bed, sleepytime tea, maybe some melatonin. While the solution is being found there is comfort in knowing that the body and brain are returning to normal through this process.
Consult your doctor before adding new substances, even herbal ones, to your diet.