dd1 is 2y10m and doesnt sleep through. dd2 is 7 months and doesnt sleep through.
sleeping through, whatever that means, is grossly overrated. just accept that until they are 10 or so you will have to get up in the night sometimes, and go with it. Accepting it has changed my life for the better
having said that, dd1 was atrocious, up all night for hours, nothing worked, and now she goes to bed more or less on her own, wakes up between 1 and 4 and comes to our bed by herself, we dont even wake up. for me, that is excellent progress and seems to be completely within the norm of her peers.
so things will get better. as my dh says- every bad night is one less bad night you'll have to go through