Hi,
I have read your question,
I have had a few patients visit my clinic with this problem , insomia though curable by allopathy medicine, sometimes mental preparation and readiness can defeat this problem also ,
bipolar disorder as you stated can be a concern for this problem also , it is primary for you to try to relax yourself as much as you can have positive thoughts,
let me explain you for instance , thinking that "Lots of people struggle with sleep from time to time. I will be able to sleep with practice." is positive than telling yourself that I should be able to sleep well every night like a normal person.
I suggest you to do
meditation , Increase light exposure during the day ,Avoid stimulating activity and stressful situations before bedtime.
Any treatment other than taking medicines can take it time to act.
So keep a light of hope and think positive.
Try these steps for some days and check the extend of relief you have and if the problem persists feel free to comeback anytime.
Wishing you a good health
Dr.K.Sanga Reddy