What Causes Nausea Along With Excessive Sweating And Diarrhea?

Hello, I am a 48 year old woman who was in good health until a couple of years ago. I had my thyroid removed in December of 2013 and since then we have had a very hard time getting my TDH levels where they should be. I suffered an episode of hypocalcemia several days after my thyroid surgery and then was fine until the following August when I had an attack consisting of rapid heartbeat (over 200), severe headache, sweating, nausea, I was kept in hospital for 2 days then sent home when nothing significant was found. I returned to the same hospital 2 days later in the midst of a heart attack. I had a stent placed the next day and things appeared fine. Since then I was recurring spells where I get very shaky, nauseous, sweaty, and often have diarrhea, these attacks will often last anywhere from 10 minutes to maybe an hour. My husband thinks they are simply panic attack but I disagree. Any ideas?? I am getting desparate. Again I am a 48 year old female, I weigh around 160