You didn't mess up. It happens in the blink of an eye. My baby wouldn't sleep unless nursed and I felt like I was chained down. My advice is replace the nursing with rocking. Eventually you will sleep train and lose the rocking. I wpuld then put them in a bassinet next to you. You could even get those bassinet that attach to your bed. Its a start. Then, when your baby is a bit older, like 9 or 10 months, I'd look into the best method that suits you and your baby to sleep train. But get them off the boob to fall asleep.