It looks like your band may have slipped, causing some tightness.
You should get some X-rays to confirm this, but first get in touch with your band surgeon.
It's more common than what you may think.
Keep taking liquids in small amounts, several times daily.
I would suggest to include some pure coconut water-not the cheaper kind with added sugars- as it is naturally balanced for electrolyte replenishment, until you get assessed.
Also for protein intake and minerals, use pastured bone broth ( slow-boiled bones for about 24-48 hours from grass-fed animals)
Cheers,
Niko