I think a long wind down would be my suggestion too. I always pick
DD up from playing when she starts looking tired and carry her around until she starts rubbing her eyes. I find if I get it right she goes down a treat, without even a grizzle. BUT if I don't wind her down like this she cries until I feed her to sleep!!
I have always found the whole sleep thing a real pain. I also had/have feelings of failure when she doesn't sleep, but as others have said, as soon as I just think "whatever" and let it go, the better I feel...its seriously not worth getting yourself down about (I know this doesn't seem to help when you're exhausted and angry). I try to tell myself that I might not be able to change
DD's sleeping yet...but the one thing I can change is my feelings towards it.
My
DH said to me the other day "sleep is not a metric"...meaning it shouldn't be a measure of how successful we are as parents, how "good" our baby is or how "good" our day went. I found that really helped...sleep is important I know, but it shouldn't be the ball breaker for your feelings towards yourself and
DS.
Sending you big hugs!!!!