Hey. I had thyroid cancer six years ago and while obviously, nobody wants any form of cancer, it isn't as bad as you might be imagining. 

The most common forms of thryoid cancer are very rarely life-threatening, especially if you are under about 50 (as in the most common form has a 99.something% survival rate among people in that age group) and ongoing treatment is rarely necessary.

The odds are the operation will sort it out but you might need radio-iodine treatment afterwards to reduce the risk of reccurence. That isn't as dramatic as it sounds. It's really just taking a capsule. It's a NUISANCE because you have to remain in isolation for a while afterwards because you are radioactive but it doesn't make you sick or anything.

Spread to the lymph nodes is very common with papillary thyroid cancer and doesn't affect the prognosis, though it may raise the chance of reccurence.

I had a 10.5cm cyst on my thyroid, 6.7cm of which was cancerous (nope, not milimetres) and spread to 8 lymph nodes. I had a 7 or 8 hour operation, was pretty sick from the anaesthetic for about 12 hours or so after that, was back at work a month after the operation and have had no problems since.