On the detail: timing is the most useful diagnostic feature here and it is the one most often omitted from the question.
Constipation outlasts the nausea because it has two causes and only one of them resolves. Gastric emptying accommodates over weeks; total intake, and therefore stool volume and the osmotic load reaching the colon, does not recover until intake does. This is why fibre alone can make it worse — you add bulk to a system that is short of water and short of motility.
Pancreatitis red flags worth memorising rather than looking up: severe, persistent epigastric pain radiating to the back, worse lying flat and better sitting forward, with nausea and vomiting that does not settle. That combination is an urgent assessment, not a dose adjustment. An isolated lipase elevation without that picture is common and usually not pancreatitis.
Telogen effluvium following substantial weight loss is documented independently of any pharmacotherapy, which is the cleanest argument that the rate of loss rather than the agent is the primary driver.
Fix the fixable causes first — fluid, electrolytes, sleep, intake — before concluding that the compound is responsible.