Methimazole only has a half-life of 6-13 hrs, so yes, if you stopped it 4 days ago, it could be out of your system and you could be having symptoms of being hyper again...
What was the cause of your hyperthyroidism and what antibodies did your doctor test?
Can you get a thyroid panel done that includes Free T4, Free T3, and TSH? That would tell us exactly what your thyroid is doing.