My 19 month old had been sleep trained for several months where I would just put her down in bed and she would put herself to sleep with no problem. About 3 weeks ago she all of a sudden started screaming as soon as I would put her down so I think we fell back into the bad habit of having to rock her to sleep. We are wanting to get her back in the routine of putting herself to sleep but I'm not sure the best way to go about it. If I just put her in her bed and walk out she screams and cries to the point of throwing up. Any suggestions on best way to sleep train again a toddler this old?!