So my usually good sleeper DS (9 months) has slept from 7pm-7am from around about 4 months but for the past 6 weeks has been waking up at 4am sometimes he goes back to sleep other times he just cries. If on the rare occasion he does go back to sleep then he wakes up again about 30 mins later. I'm reluctant to get him up at this time as that's just a ridiculous time to start the day. Both me and DH are exhausted as it's everyday and it's taking it's toll on us. I have gone back to work too so not as if I can nap when he does. I have tried changing his daytime naps so he doesn't sleep past 2.30 (2, 3, 4 routine) but it hasn't helped at all. We don't take him out of his room we treat it as night time. He just cries and cries and doesn't settle. He's not hungry, doesn't need his nappy doing, I'm at a loss. Any advise greatly appreciated. I know if been extremely luck with his sleeping pattern before but this is killing me