You are NOT cold. You are wonderful. Look, I've been through this with family members, though the "job" was shared amongst us, and I didn't have to go it alone. (It sounds like you had help, which is good.) I think that your experience with your aunt and those who are pressuring you has made you second guess yourself and make you feel as though you did things badly. You DIDN'T.
Your family cannot dictate all this stuff for your life, from taking care of your mom for 18 months, to selling the house and turning off the phone. It is wrong for them to. We are supposed to take care of business after a death. It has to be done and if you were the one to do it, so be it. Your mother would be proud of you and if she CAN see now from the other side, she IS.
People deal with what you dealt with, a loved one who does not want to be in the hospital, all the time. For those of us dealing with dementia or post-surgical "brain fog", for lack of a better term, we have to be tough and make the call that they can not go home. It is hard, even for those who HAVE discussed and put in place a DNR and medical power attorney. That doesn't make you cold.
Your aunt didn't have to make the hard choices. She of course felt frustrated that she couldn't "save the day", but what she isn't seeing is that she could not. If the decisions fell on her shoulders alone, she would have all of a sudden realized the gravity of letting your mom do what she wanted, seeing her suffer greatly, and then having the GUILT of making her continue to live in pain by not honoring that DNR. You have saved her this. Of course, she cannot see it. I would say that she would have been unable to settle her affairs because she is too emotional.
Do not second guess yourself anymore. But at the point when you have HAD ENOUGH of hearing "you don't feel with your whole heart like I do" from you aunt, either tell her that she will stop saying that to you or you won't see her anymore, or leave everytime she does.
You say that you don't expect them to be like you. Honey, they aren't being like most people. Most people act like you, not like them.
I want to add to you to rent the movie "Sense and Sensibility" starring Kate Winslet and Emma Thompson. Kate tells Emma that she doesn't have a depth of feeling because she is reserved. Later in the movie, when the situation comes to a head, Emma (Eleanor) tearfully tells her sister that if she hadn't been bound to a promise, she could have produced evidence of a broken heart enough, even for her. It is a poignant and telling moment between them. Hers is emotional, without anger. But perhaps if it gets to the point that your aunt seems to never be willing to release you from her guilt trip, you should get angry enough to act like Eleanor and show her how you feel, without reserve.
All my best,
Dawn