I will start by saying that adjusting to night shift is a beast all its own. I've been doing it for 3 years and sometimes it still feels just as difficult as when I first started. It helps to get into a routine, and to practice self-discipline. Be in bed no later than this time, force yourself up and out of bed by this time. If you have any hobbies (art, reading, yoga, running etc) try to devote 30-40 minutes of your time to a calming hobby or maybe just a cup of coffee and some music before you start getting ready for work. When you get home from work, try to redirect your thoughts AWAY from work. It's normal to come home and ruminate on the shift's happenings but I promise this will only stress you out more.
If you know in your heart of hearts that you want L&D, that's one thing, but I have friends who have had great success devoting a year or two to med surg, step down, one even started in ICU and then transitioned to L&D. You develop critical thinking skills and time management in these areas, something that will likely benefit you in the future when you trasfer to L&D, or wherever else you find that you may like!!
Good luck! Don't be discouraged! You worked hard to get here and you have years to go, unless you decide to choose a new career! It gets better with time