If you are getting only 4 hrs of sleep recently and then you should not take it lightly.The underlying depression
, anxiety may be there which may cause such insomnia
You should daily do exercise, eat healthy food and may take melatonin
in the dose of 1.5 mg at nighttime to control the symptoms.It is available as otc without prescription.
If the symptoms are not controlled then consult your doctor/neurologist
The adequate sleep is necessary for the healthy brain.