I noticed in another reply that you had blood work yesterday. Hopefully your tests showed some improvement in blood numbers.
Have you told your doctor about the side effects you’re experiencing? There are members who have mentioned that their doctors have decreased dosages once the blood numbers have settled into a comfortable ‘norm’. Sometimes that’s all it takes to find the sweet spot for the medication to balance side effects vs optimal dosage.

Considering that you were diagnosed over 12 years ago with ET but never had any issues, what changes prompted your doctor to have you start treatment? Were your platelet levels rising?