Insomnia is very common while pregnant hun so it might not just be the caffeine. Look up "sleep hygeiene during pregnancy" might help u find relaxation throughout.
Herbal mint tea is very soothing. So is chamomile. I sip chamomile most of the day because I am a voice teacher and talk and sing all day long. It is soothing to the throat. I love herbal mint tea at night. Both are caffeine free. Before the baby I also drank a few cups of coffee a day. But the tea has become a new ritual.
Be careful cause green yea has caffene try to stick to herbal teas. My dr suggested lavender chamomile and mint. There is a brand that has teas for pregnant women but I prefer the sleepy time from celestial seasonings.