
I'm really sorry you're having trouble sleeping and it's driving you into these horrible rapid cycling/mixed states. I really hope it passes soon.
Have you ever tried a classic sleeping pill? I'm on Trazodone (although it's an AD of course) for sleep and it works well.
But anyway your doctor has given you Ativan so definitely go with that. I wouldn't start to question whether it will work or whether you'll pull out of this. It'll stress you. Assume you will. Say to yourself 'yay, I have my Ativan, I'll sleep, and soon this will pass ' - you know? But - easier said than done of course.
Ditto your husband - he'll stay up with the baby if he said he would. So put that out of your mind, and just sit back (or lie down

) and get the sleep you need.
I really hope it improves.