Duration of MIRNITE 7. 5 mg. 15 mg?

I am taking Prodep 20 mg for last 7 years. From the last 3 months I was having mood swing, low mood , fear during sleeping, Urge to call in mobiles 30-40 times a day . So, I have consulted a psychiatrist. He told me to continue Prodep 20 mg in the morning and prescribed another 2 medicines at night . One is MIRNITE another is ATIVAN . He told me to take MIRNITE 3.75 mg (half of MIRNITE 7.5 mg ) for 20 days. Then from 21st day he told me to use MIRNITE 15 mg . And from the very first day I am taking ATIVAN 1 mg after his diagnosis. My question is whether is it okay to increase the dose of MIRNITE from 3.75 mg to 15 mg in the 21st day. Or should I take MIRNITE 7.5 mg from 21st day for few days and then move into MIRNITE 15 mg ? Please give me suitable suggestions for increasing the dose of MIRNITE gradually.