Aw mommy, nakakabahala talaga yan! Honestly, a few of us moms struggled with weird sleep schedules during pregnancy din, and our OBs said it's common but best to try adjusting little by little kasi the baby needs consistent rhythms too, mas maganda if you can shift even 1-2 hours earlier every few days. Puyat ka talaga ng matagal, so definitely mention this sa next checkup mo para may proper advice sila based sa pregnancy mo, but from what I've heard from other moms, the fact na may tulog ka pa (even kung late) is better than walang tulog completely. Try to get more light exposure during morning hours to reset your body clock, and maybe avoid screens before bed, it helped one of my mum friends!