Please let me know I am not alone

BabyD316

So my son is 12 weeks old and we thought he was getting this sleeping thing down.  He was sleeping in 2-3 hour stretches.  He even slept 5 hours straight Monday night.  Starting Tuesday he won't sleep any longer than 50 minutes.  Today it has been only two 25 minute naps.  He sleeps well while being held, but wakes up soon after being laid down in his RnP.  We have tried laying him down drowsy but awake and completely asleep.  We have way more "success" lying him down asleep.  I am so frustrated and exhausted.  I just don't know what to do.  He falls back to sleep easily at night when he wakes up and is not hungry.  I can't keep doing this.  Any suggestions would be greatly appreciated.

 

Those of you who have a baby STTN are so lucky!  I know some of you have babies who STTN but only nap 45 minutes at a time.  I would kill for that!