Diabetes Insipidus water intake question

I was recently diagnosed with Diabetes Insipidus due to frequent thirst and extreme daily urine output. I have just been put on Desmopressin 0.2 MG tabs, 1 tablet by mouth twice daily. After reading about the drug I learned I should be limiting my fluid intake. My question is how much should I limit my intake? Should I drink the recommended 8 glasses of water a day? Should I drink less? Or should I drink more because my body is not yet used to restricting my intake so much? Prior to my diagnosis I would drink about 200 to 300 fluid ounces of water a day and still feel thirsty. I have been taking this medicine for about three days. For reference, I am a 22-year-old female, moderately active, 5'5", ~118 lbs. I have been getting headaches and I think it may be because I am either drinking too much or too little water.