Have you tried Headspace? There are ten free meditation sessions and then you can decide to pay a subscription. There are sessions especially for sleep but all of them make you feel much more relaxed - it makes me realise how tense I am when I go to bed sometimes, when I think I'm knackered and ought to sleep like a brick.
I should say my problem is not usually falling asleep but staying asleep. Even if I get up for a wee at 4am, if I've meditated at bedtime 90% of the time I'll go straight back to sleep.
I have a routine where I massage my feet with creme sitting on the side of the bed in the darkened bedroom. Then I lie down and do my headspace meditation. Then if I haven't gone to sleep already, I put on a podcast on BBC Sounds, a drama or anything with people talking (speech seems to work better than talking) that I'm half interested in and drift off. If it's long, you can set the sleep timer to switch it off after 30 minutes or so.
Also think about the temperature of the room, it's muggy at the moment. I have a quiet tower fan on and the white noise sound seems to aid sleep as well. And the darkness of the room. My curtains keep out most of the light, and I just have a tiny nightlight plugged in.
It can be hard to get comfortable when pregnant in any event. Experiment with putting a cushion under your bump and so on.
Also, I assume alcohol and caffeine aren't a particular issue at the moment, but consuming more than one glass of wine in the evening will (boringly) disturb my sleep. And I can't have more than two cups of coffee in the morning.
Eating can affect sleep as well, especially when you are pregnant and your digestive organs getting squashed. Try eating your evening meal earlier and nothing rich.