Help with my 22 mo daughters sleep

My daughter is 22 months, she is becoming a nightmare at night. After 3am she can wake every 20 minutes crying till she finally gets up at 7/8am. Some mornings she’ll wake up 5 times then sleep till 8. But it’s exhausting, when I go in her room she’s like half asleep, has her dummy and I have no idea why she’s even upset. I’m stuck in a complete rut with it, it’s making her tired and also me. Maybe once every 2 weeks she will sleep all night, sometimes she just wakes once but last night was horrendous. Please can I have some tips.

*She eats three good meals per day

*She naps from about 2-4pm (do I need to make her nap shorter and earlier? Although she seems to need it)

*Bed between 7-7:30pm and self settles

* She has a bottle of milk at 7pm and I still have to take her one in at 11pm like a dream feed for her or she’ll wake up!

* She always without fail gets out for a walk and fresh air

Until about September she was absolutely brilliant at sleeping, I have no idea what’s happened.

I’m 32 weeks pregnant so really need to get this sorted before baby comes :(

Any advice welcome! I don’t know what I’m doing so wrong :( I try and let her self soothe in the night but she just doesn’t stop crying it’s exhausting me.