I know you are at the end of your rope, but if you can arrange with DH that you two will work together on this issue, I think you can both fix this - but you need to help each other since you are both so frazzled and ready to give up. re-implementing these things will take a little more work and you may feel like you are doing it for nothing or seeing no benefit. While I know that it feels like forever when a baby cries, you mentioned you've been at this for 2 or 2.5 weeks - that really isn't a long time, and to be honest, it isn't enough time for baby to have completely adjusted to it - not to mention I am not sure you guys have been doing all the BW stuff properly (I don't mean to offend) and this is understandable when you are tired - I break her rules all the time and still do and feel guilty but that is another post!
Back arching is a sign of extreme fatigue. My son is 8 weeks today and can only stay awake 45 minutes, and sometimes very rarely 60. This latest stretching of the time to 60 has only happened this week and really only about 10% of the time. I watch him like a hawk from the time he wakes once his feed is done, and this means I don't grab breakfast, don't pee, don't leave him lest I miss the window because if I miss it by even 5 minutes sometimes, it screws things up. I am going through it right now as DS struggles to stay asleep because I waited too long while getting DS breakfast. He yawned at 15 minutes and I thought "he can't possibly be tired yet, let's wait and see" - big mistake, so we are all there in some way or other.
I would say, like Debinoz mentioned, to pull back your sleep. 90 minutes is a really long time for them at that age, and for some, it may take months before they can stay awake that long. You can't follow a book verbatim and expect that they will conform to a routine set out in a book - they aren't robots after all, and like you and me, they have some days where they can stay awake longer, and others where sleep is all they want to do.
Remember that when he is crying, he is really saying "mommy please help me fall asleep, I am so tired" - he needs you. CIO while tempting at this point will only set you very far back, and if you have the latest book by Tracy, can lead to room fears (sounds like you have those somewhat now) and that can take up to 4 weeks to resolve using her plan.
Start fresh today, since it is Monday and consider it a fresh start. Aim to have your baby back in his bed at the 45 minute mark. You may have a baby who by the time he first yawns is already tired. This is part of learning him i.e. does he have any reserve after that first yawn, or is it too late by that first yawn? Every baby is different and you will find that he himself changes where now he has no ability to stay up past the yawn, but in a few months he will - you need to adjust along with him.
Maybe you and DH can take turns with the evening wind down so that at least one of you gets a break. Perhaps the one who doesn't do the bedtime routine can do something nice for the one who does - massage, bath, etc...so that you are truly supporting each other through it.
Do try implementing the dreamfeed. It happens from 10-11 and in your case I would start at 10:00 since he sometimes wakes before that. If he is waking at 9:30, maybe even do the DF at 9:15 before he wakes to prevent the wake, and then a few nights later push it to 9:30, then 10:00 and hopefully this will let you guys sleep past that first wake a little more.
When he wakes at 2:00, why do you give him a short feed? THe feed he is taking at 10 or so is not considered a "night feed" and babies need one night feed usually at this age. By giving him a short feed you are creating his need to wake at 5am for another one cause he didn't get enough at 2. He will then keep waking and be unsettled because this is now his third sleep interruption of the night since going to bed, and he is going to wake exhausted.
I think we need to also remember that babies are like us - if he is having his sleep interrupted three times in the night, he will wake tired. I will bet that his first awake period will be very short on mornings when he had a bad night like that. We would be the same. I had a rough night last night and that likely explains why DS was yawning at the 15 min mark. I just didn't believe it, and so here we are waking every 15 mins into the nap unsettled and getting progressively more tired - my bad.
I hope this works out for you guys. Remember to be a team with the end goal to be to get his daytime sleep sorted out - the night follows all by itself when the day is good.
