No, I don't think that is anything to worry about. It is probably exactly what they said. They don't think it is cancer but they need to check to be 100% sure. This is very common with thyroid nodules and in fact, it's not uncommon for them to have to remove half the thyroid in order to tell for sure (though it doesn't sound like this is likely in your case) and even in those cases, it is generally not cancer.

Thyroid nodules are extremely common and it seems like it's often difficult to tell if they are cancerous or not. My ENT was talking even before they did the FNA about what would happen if it came back inconclusive. He appeared to think that the most likely scenario.

Even if it was cancer, thyroid cancer is...well, not as bad as most cancers. Obviously, nobody wants to be diagnosed with any cancer but it isn't what most people imagine when they think of cancer. It's usually just a matter of removing the thyroid. And it is very rarely life-threatening.

Waiting is always going to be a bit concerning as there is always the possibility it could be cancer, but it sounds like they don't think it likely which is definitely reassuring.