What could I have done different?

Can't seem to get the pit in my stomach gone.  I'm constantly wondering if I could have done something different to help Virginia.  Like could I have done more research on Ocular Melanoma?  Could I have searched for doctors that specialized in melanoma.  Should I have recommended my Oncologist and if she couldn't help Virginia, maybe she could have recommended someone in the area that could have helped her.  What could I have done different? It just breaks my heart that she's gone.