You could try valerian tea. Or melatonin.
But most important is to relax. try and go to bed always at the same time. You need to associate the bed with a plave where you sleep, not a place where you have difficulty to sleep. Read a book, take a hot bath before going to bed. Drink a glass of hot milk. All of this will induce sleep.
Melatonin worked very well for me.
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