Blood in the vomitus is a sign of upper GI bleed which can be due to
Stomach /
duodenal ulcer ,
Oesaphagitis or inflammation of the food pipe
gastric erosions induced by drugs like aspirin , pain killers ,
Gastric cancer ,
the colon polps and the blood in the vomits are not related .
the only way to document upper GI bleed is
endoscopy which you said that your insurance will not authorise .
You have not mentioned which country you are residing in.
If you were in Canada I suggest you can go to USA and get it done privately without much waiting time if you can afford it.
otherwise you can ask your
primary care doctor to ordera
barium meal which is ainferier test because you cannot biopsy any lesion if you see one.
Cut down oil and spicy food
dont skip meals
stop dairy products
no soft or energy drinks
no alcohol no smoking
stop meat products
Eat a plant based diet
eat lot of fibre rich veggies and fruits .
keep moving for your bowels to move
you might get good relief with these measures till you figure out your health insurance issue.