Had a similar problem, lost enough blood to get anemic. Had all the tests including swallowing the “camera pill before they finally figured it out. They found seepage in my duodenum. They sealed it with an argon laser treatment. I had to then take a series of iron infusions to get my strength back. I’m ok now.
Good luck, I’m sure they’ll figure it out and you’ll be ok.
My dad had the very same thing about 15 years ago. They took care of it and he’s absolutely fine now.