First things first. Surely you will not die if you are able to sleep for 4-5 hrs per day. What you have is acute insomnia
. These may because of stress
or change in sleeping conditions. You should avoid any stimulating activities at night, avoid caffeinated drinks post evening, go to bed only when you are sleepy , do relaxation exercises, read a relaxing book before retiring to bed (mind you let it not be a thriller) and not worry about inability to sleep. Try maintaining a good regular sleep hygiene
. That will help you.