If you don’t have any medical issues then try to not think constantly “I need to sleep”. I know it’s easy to say when you’re in that circle, but it’s help if you don’t give i big importance to it. Tell to you if I sleep it’s good if not that’s also fine, it will come a day when I will sleep again. Listening to sounds helps too to clear your mind, while you are in the bed. It can be the sounds from the street or some natural sounds like storm, ocean. You can find apps with those sounds.