18 month sleep regression

My daughter is almost 19 months and the past few days have been absolutely terrible. Last night she didn't go to bed until 4am. We tried literally everything we could to get her to sleep and she just cried and cried. Getting her down for naps and bedtime is so hard because she just cries and resists sleep until she eventually passes out an hour later with us holding her and rocking her. How long does this last? I'm losing my mind 😭 and I'm running on 5 hours of sleep while 23 weeks pregnant.