What Causes Excess Sweating And Fluttering Heart While Being On Levothyroxine?

I am 50 yr old female and I have started breaking out in sweats feeling jittery and my heart flutters and pounds. I have a histroy of thyroid disorder and had rt thyroidectomy 5 yrs ago.I had my thyroid levels ck and all were normal.I am also tired all the time and also going thru menopause. I m not sure if my symptoms are related to thyroid menopause or something else. I am on Levothyroixine 50 mg daily.