Help with sleep training issues

Help. I tried to sleep train my son at 12 months, starting 2 months ago, using the Ferber method. At first it went exactly like the book said it would. He cried off an on for a total of about 4 hours of crying the first night (an hour at initial bedtime, then 3 wake-ups with an hour of crying each).The next night went much better, with about 40 minutes of fussing and only maybe 10-15 minutes of true crying, and a little light fussing overnight.The next night, he fussed for about 10 minutes and then slept through the night.Since then, though, his pattern has been to scream bloody murder for 10-30 minutes when I first put him down. I don't mean a little grumbling, I mean screaming so hard he chokes and coughs. Every single night for 2 months now. I stopped doing checks about 6 weeks ago and nothing has improved.He does the same thing at nap time as well, sometimes crying (alternate light fussing and full-on screaming) for a full hour before falling asleep.He starts screaming as soon as we head toward his crib and he clings to me. Once I put him in his crib, he can't be soothed, and if I try to pick him up he thrashes and bites me.I'm starting to feel like sleep training was the wrong choice. We used to nurse to sleep at night and nap, and as soon as we headed toward the nursing chair he started to giggle and almost pant like a puppy. Seeing his reaction to his crib now breaks my heart.Also, he doesn't seem particularly well-rested. He still wakes often at night and even though he doesn't cry anymore, I think he has trouble falling back to sleep. Sometimes when I wake up I see him awake on the monitor and he looks bored and restless.I want to move toward weaning him totally, but I almost feel like, if this is our new normal, I would rather go back to nursing to sleep.What am I doing wrong? How can I fix this? via /r/Parenting http://ift.tt/2lPt91H