Feel like i can smell blood/iron. but theres no blood. it comes and goes. is this a sign of internal bleeding or a stroke, brain aneurysm etc? stomach bleeding? basically is it a sign of something bad and should i head to hospital?

Not to the hospital, but talking to your doc at your next visit would be best. Parosmia is a possibility and is many times challenging to diagnose, while some other times micro hemorrhages involving the mouth, nose and throat area may substantiate the smell. Seeing your dentist timely will help, too, in further trying to explain the possible provenience and persistence of the smell.

Would explore possible issues involving upper respiratory tract (nasal, sinuses, etc.) with an otolaryngologist. Chronic problems are not appropriate for an ER visit. This is not due to central nervous system problems such as stroke or aneurysm. Although some patients with epilepsy will experience olfactory auras, this does not appear to be your issue.