Hi! Does anyone have any successful sleep training advice/tips/programs they would recommend?!

My 16 month old slept great from months 3-5. Then we both got COVID and I swear it was never the same. It was literally just about a year ago and I think she has slept maybe 2 nights all the way through since and I am so tired and desperate for consistent sleep.

We unintentionally started co-sleeping because it was the only way I could get any sleep. I try to always start her in the crib but lately she wakes up about an hour later and I can't get her back in. We are still nursing at night - again just because it's about the only thing that soothes her and she's teething.

We have tried crying it out but she is so persistent and her scream is intense. I have a 4 year old whose room is across the hall so it makes it difficult to follow through with that without waking him up.

Anyone tried anything that was really helpful at this age?!