Wa'alaikumassalam sayang! First thing, go tomorrow like the hospital said, okay? They caught it early which is good, and they'll guide you through what comes next. I know it's scary with a newborn, but honestly hyperthyroid conditions in babies boleh managed, especially when they find it this fast. The doctor will explain everything properly tomorrow and buat the next steps clear, try to rest your mind until then, and bring your hubby untuk support, okay? You're doing the right thing by following up. Sending you strength, mama.
Jee Nasir