My 15 month old has always gone to bed well between 6.15pm-7pm he usually naps a total of 2 hours over the course of the day (no sleep later than 3.30pm). He has always been an early riser around 5.30am (he may do a week of 6am/6.30am but very rarely) but for the past few months it's been around 4am and will occasionally cry a few times in night but will settle back down but the 4am wake up he refuses to go back down. He is clearly tired and is ready to nap around 6.30am... he has been teething for what seems like forever! His back teeth are nearly all through which I know has been sore for him but is this normal to cause such a disruption to his sleep? I am exhausted and is putting a massive strain on me and my partners relationship. Any tips welcome 🙏🏼 thank you.