Tired

I had half of my thyroid removed 6 weeks ago and I am apsolutly exhausted all the time. I'm sleeping constantly. 

I have also been told that when they removed the thyroid there was more cancerous nodules. Which they beleave will be on the other half as well. 

I don't know if to have the surgery to remove the whole thyroid or if to monitor it. 

I'm super stressed about it all atm I have no idea what to do. 

Any advice please would really help.