i am having this same problem as well this week but i just started slin too. after my thick ass shake made up of pretty much exactly what you are taking, i dont really want to eat but dinner is usually ready in 30-60 min. sometimes i sit ant the table for an hour pushing that food down. thats at 7pm. then around 9:30 my stomach growls and i make a shake and a snack and go to bed.
i wonder if digestive enzymes with the shake would help at all??
Back off the slin, it always made me feel like puking, so much that I wont touch it anymore.
For me it was just to much hassle, to carry around packs of sugar, or glucose pills(I used Smarties) just in case.
You are getting hungry again because of the slin as well, sounds like you are running type R.
I would also look at the label as to what kind of whey protein is in your shake, companys are great at fooling people useing cheap whey concentrate, which always killed my stomach.
Find yourself a good whey Isolate, make sure its listed first in the label is there is other types of whey used.
Try Isopure, it is more pricy than the other brands but is an isolate, which is much easier on the stomach.
If you want a quick tip for a good cheap digestive enzyme, buy some fresh chunk pineapple, eat 2-3 small chucnks, I always did this when contest dieting, it worked like a charm.