Blood tests don't always show everything.

What about a colonoscopy? If you are having tons of digestive issues, that should likely be done. There's also nuclear tests that can reveal a lot about the digestive system.

And I agree with @healingme4me . Seek out specialists. If you need referrals, then get a second opinion with a different PCP first, one who will refer you. Even if you don't need referrals, you should get a new PCP anyway. You need to trust your doctor will do right by you, and it sounds like this trust isn't there.