There are cystic (fluid-filled) nodules, solid nodules, and complex nodules (mixed solid and fluid). Cystic nodules are not concerning unless they are getting so big they are compressing something in your throat. Solid nodules need to be scanned to see if they are "hot" (overproducing thyroid hormones), warm (producing hormones but not at high levels), or "cold" (no hormone production). Cold nodules are suspicious as are complex nodules.
Nodules rarely affect thyroid levels (unless the nodules are overproducing hormones) so having acceptable levels on your blood tests doesn't mean you are out of the woods.
Get the scan and get a good endocrinologist who specializes in thyroids to talk to.