Uy, alam ko yan! Ang 4-5 month regression is real talaga, grabe ang stress, one of my close mum friends, her baby was waking up every 2 hours din at first akala niya may problema na sa baby. What helped her was consistent bedtime routine (even just 15 minutes ng gentle play, bath, then feed), and honestly, a lot of patience kasi it does pass, usually 2-4 weeks lang. A few of us tried white noise din, parang sound machine or just fan, and it helped settle our babies pag nagising sila sa gabi. Kaya mo yan mama, this phase won't last forever!