It is common for the blood numbers to take awhile to improve. I am Jak2 positive as about 90% of people with one of the 3 MPNs; you are in the 10%. Glad you are in the oncology department as that is where you will have the best advisors to discuss your options.
Once your numbers are in line hematocrit less than 45 they consider you more stable. Ask what numbers your doctor is using as indicators, what numbers are outside of the normal ranges and do research on what those are showing. Platelets, MCV, RDW, hemoglobin etc. Have they checked your blood pressure and/or spleen and liver sizes? Common for high blood pressure as well as low hemo and high platelets if you have low MCV numbers your red blood cells are small and immature common, if you have an enlarged spleen it can remove additional red blood from your system removing hemo further reducing that number. I took my second dose of Pegasys this week with little side effect. It is expensive especially without drug coverage, but something to discuss besides HU. Stay as positive as you can, be your own advocate and you can live a long time fighting the good fight!