An actual side effect to WLS is nausea, because well, you let a surgeon mess with your stomach that houses a ton of nerves and you've ticked it off and so in return, it is going to give you a hard time as well!
You should contact your doctor with your issues and tell them what's going on. I battled extreme nausea for 5 months. There are helpful drugs out there to settle things down. I took Zofran and put a patch behind my ear for most of that time. Wasn't 100% but it was effective about 85% of the time.
Also, not getting in enough protein, especially right after surgery will cause you to be sleepy all the time. Protein = energy!!! No matter how you get it, you need it. If you don't figure out how to get it, you go back to the hospital and they force you to get it. There are unflavored protein powders that can be added to just about anything to get your protein in daily, not to mention a market full of premade stuff.
As far as the throat thing, yes, that is also a side effect. Try drinking a warm liquid like tea slowly to loosen up the throat area before you try to drink cold liquids. It will help get the liquids down and sooth the throat. Best of luck on your recovery!
