How can i sleep train when my 5 month old cries for 1 minute and then start throwing up??

nicole
I don't know what to do. It's almost 11 and he's still up. I got him down at 8:30 and he woke up at 9 and has been up since. I finally just gave up on putting him back to sleep. It's been like this for a week now. I don't think it's sleep regression. I believe we went through that last month.