I had echo for a new heart murmur that appeared 6 months ago. i was told that i am fine. i have fatigue, fever, splinter nail hemorrhages and blood+protein in the urine. could it still be endocarditis despite the normal echo?

Yes: It's possible and transesophageal echo is more sensitive so it may be time for a tee.

Absolutely: You have endocarditis and need to be seen and treated by infectious diseases experts asap. Echocardiography, even if done at its best, does not exclude the diagnosis and you have most of the criteria. There are many cases of culture-negative endocarditis. If you are not being seen by an id expert you need to do that now. There are serologic studies to identify organisms (like coxiella burnetti).

Yes: An echocardiogram which is negative does not 'rule out' endocarditis. It just means that whatever is there isn't seen on echo. You have too many other positive signs. Get blood cultures.