Remeron help

Is it safe to go back and forth on Remeron dosage?
I was taking Remeron(mirtazapine) for 4 monthes. I had a sudden yet long occurence with anxiety, and it caused insomnia too. The doctor put me on Remeron for the time being. It helped pretty well. 15mg per night.
i started feeling bad again last month. Went to the doctor and she tested my adrenals. They came back relativly high with low testoterone. She decided to try adrenal medication on me hoping my anxiety and issues were stemming from that. She thought it would be a good idea to get off the Remeron , as my body is sooo sensitive to medication. I tried. I cut it in half, skipped every other night, and my anxiety came back with a vengeance. I don't know if its from the discontiuation of it, or my anxiety just got worse. I took a half last night and finally slept again. Doc said if I have to go back to original dose to stabilize, that would be ok , but that was over a week ago. Shes out of town so I cant call her, and I was wanting to go back to the original dose tonight, as my anxiety is terrible, but being that I have been all over the map with dosages the last 2 weeks, I didn't know if it would really mess me up jumping back to the whole 15mg. Please help if you have any knowledge of this. Thank You.