Q. My dauschund just found out has diabeties hes throwing up blood very week won't eat or drink should I put him down
A. I'm sorry you are going through this.
Making the decision that it is time to let a pet go is a difficult one, and a personal one. It is hard for any of us to gauge this situation as we do know about his case, all the symptoms, prognosis etc. Typically throwing up blood is not good. Are his meds keeping him stable?
If it were my own dog, I would look at good days vs. Bad days. If he is still having good days, gets excited about things, enjoys his favorites (food, treats, toys, games, walks, etc) those are good signs. When they start to no longer enjoy the things they once loved then you know something is wrong. When the bad days pile up and the good days get fewer then you know its getting close to being 'that time'.
Whatever you decide, the choice is yours. He isn't going to hold it against you, that's amazing thing about dogs. Enjoy the time you do have left but before he goes help him celebrate his life: spend the day with him, show him you love him, go for a leisurely stroll at his pace, have a party, feed him a burger, let him eat a ice cream cone if that's what he likes then let him slip peacefully after a beautiful day spent with you, his favorite person.