I know this is a very old post, and you are more than likely ok now, even though you still miss your dog. I just lost my yellow lab Mr. J to hemangiosarcoma  ( presumably ) 5 days ago. He was 12.5. I’m a vet tech and we were checking his whole abdomen by ultrasound every 3 months, then every 6 since 2014 when his bloodwork was a bit off and I was worried about this tumor. That’s 3 years. And it still took him away from me. He was all clear on ultrasound 7 months ago. Then week ago collapsed, was rushed to ER, had multiple splenic lesions and mass on liver. He died in my arms in our home when I made decision I won’t put him through surgery and more pain. You absolutely made the right decision. Dogs with splenic hemangioma that have abnormalities in cray of chest and other organs are likely to have metastasis already, since this is such an aggressive fast cancer. You loved your baby enough to let go. You loved her enough to not cause her any more pain just to make yourself feel better about few days. You be p proud. You were strong for her. That’s unconditional love.