12 week old Baby won't stop crying, it's obviously because of fighting sleep. It's been 24 hours of cyclical 30-min nap, 45-min awake/crying/fussy eating. I'm exhausted, I'm alone, and I'm running out of ideas. I'm literally running on fumes because I can't sleep in 30 minutes and baby is overtired. I've tried car ride, I've tried wraps, I'm scared to sit and hold because I'm so tired I don't want to fall asleep. Besides letting baby cry, what can I do??