There is already some great advice here. Just wanted to quickly say that yes, the losec takes at least a week to work and maybe longer for it to really get to full effectiveness. I'm not sure about which dummy but I did find a dummy helped as she was sucking on that and it seemed to help stuff stay down better. Day sleeping for my DD2 was non-existent until the Losec really kicked in, and she spent most of her first few months in the sling. I think you probably just need to ride out this stage and hopefully when she is more comfortable the day sleeps will start to appear!