hello and welcome to HCM,
Let me first of all assure you that your lack of sleep in the days of college has nothing to do about your sleep now. You may have difficulty in sleeping due to many causes. Let us exclude them one by one:
1. Since you seem to be having heaviness of the head along with a block of the nose then you need to be evaluated by an ENT who will do a proper endoscopy
and CT of the PNS and initiate a proper treatment.
2. You also need to undergo a sleep study or the polysomnography
to find out if you are getting sufficient good sleep and oxygenation to the brain.
3. You also need to take a glass of warm milk before your sleep and not drink caffeine in any form especially in the night
4. Since you were used to sleep late for all these while during your college days your body has to get adjusted to the new sleep rhythm so give some time
take care and sleep well!!
Dr Sriram Nathan