I am very sorry to read you have this illness. It's a chronic illness, it's debilitating, it's lifelong, there is no cure and you are young!
That's the thing about some of these chronic illnesses, mine is MS. Some days are good healthwise, some are not. And those, that don't have these lifelong illnesses, sometimes, lack compassion to the reality of living it!
Many of the symptoms are 'hidden', 'invisible', but they are very real.
I am sorry, that your family is being dismissive of your reality. It's not fair. It stinks, when others, say things like, well at least you don't have what I have, or you've no right to complain, because you don't have what I have. It's not an effin competition!
Are you learning how to manage it? Have you reached out to others, with the same condition?