Some mix of: reduced appetite and interest in food; getting discomfort in the general region of my stomach sooner after starting eating; frequent urge to go to the loo but mostly producing small quantities (with significant discomfort) of dry, hard, pellety stool that is Reluctant to Leave.

Gastroparesis + hypothyroid: have not actually looked into this one much, sorry! But this wouldn't be massively surprising, given that lower appetite + stool changes are well-attested with hypothyroidism, as it's fundamentally a condition that slows your metabolism down a bunch...