Abnormal thyroid test

Hi, I have for weeks suffered from fatigue, muscle weakness, weight loss, vision problems and anxiety. I have a notice goitre also. I just had some blood work done for my thyroid and I had a call to say my levels are off and the doctor needs to see me. I have an appointment in two days and don't yet know exactly what these results mean. I have been reading online that some people felt Ill even with meds and sometimes worse. My anxiety has gone through the roof and I just constantly feel like I have flu. Had anyone started meds and felt better and how long does it usually take to feel a difference?