An overactive thyroid gland leads to Hyperthyroidism whereby the overactive thyroid gland produces excess amounts of thyroid hormones. Its symptoms are Excessive sweating, Heat intolerance, Increased bowel movements, Tremors, Nervousness, Rapid heart rate, Weight loss, Fatigue, Decreased concentration, Irregular and scant menstrual flow. On the other hand Hypothyroidism is low thyroid condition where low amounts of thyroid hormones are produced. Symptoms are: Pain in joints, hoarse voice, dry skin, coarse hair fatigue, depression, restlessness etc
I am a Registered Nurse and have a sister and a mother who have had thyroid operations and now need to take thyroid hormone tablets for the rest of their lives. Myself, I had low thyroid hormone levels when pregnant so did some study of natural ways to increase these and found that the best food for a healthy thyroid is seaweed (try sushi, and seaweed soup which is given to new mothers with excellent results), or you may be able to find some Kelp Capsules at a health store which could help with balancing out your thyroid hormone levels. I don't know about the insomnia being a symptom or not, but know that high stress levels led to a quick loss of weight (high metabolism = highly active thyroid) for myself. Hope this is some help for you!