Don't know what to do.

Little bit of background knowledge before I get into the story. First of all my Great Grandmother is 89 turning 90 this upcoming March. Her health has been deteriorating slowly over the last 10 years. Due to the Asthma she's had her whole life she has to be on oxygen 24/7 to help her breathe and takes loads and loads of vitamins and pills daily for lots of things, but as of the last few years her short term memory is just terrible, like so bad you'll have the exact same conversation with her 5 times. but she doesn't have Alzheimer's. And her hearing is s bad she's legal deaf, can still hear but barely. She lives at home and her daughter (my great aunt) takes care of her. She's crazy. Super paranoid that everyone is out to get her and always causing problems and drama.
On to the story. I had sent my grandmother a card wishing her a happy thanksgiving and telling her the news that I'm pregnant. Well today I got a card from that aunt in the mail and it started off with a congratulations but turned to "grandma is absolutely devastated about this news. She sobbed and held her head in her hands and is absolutely heartbroken. I just want you to know that I DID NOT influence her negatively in anyway. You just have to understand that she is from a different era. And she's so upset about it. I don't expect her to live another year. But don't be upset with her. She does love you. So I lied and told her that you and your boyfriend are secretly married and that you'll finish college at another time."
I'm just really upset because for the first 13 years of my life I had seen my grandma every day. She was like another mother to me. And I know she's from a different time but I can't help but feel like my aunt is causing problems as always because I'm no where near being the first one in the family to have a baby and not be married. And she wasn't upset about anyone else. I honestly threw the card in the trash and cried. I don't know what to do.