Lost two friends

I lost one of my best friends on 10/28 of this year. Her name was Amber, she was only 29 and had a blood clot break loose from her leg and went to her heart. I miss her very much. About a month my friend Tk (who was also friends with Amber) got angry at me and Amber's girlfriend. She told us we weren't letting her mourn Amber and ultimately blocked me on every social media/gaming platform and then started saying stuff about me to Amber's girlfriend and on social media behind my back. I still talk to Amber's girlfriend and she says she trusts me but I'm so afraid that Tk is gonna try to hurt that friendship because she's so angry at me. I apologized to her and admitted my mistakes when it came to letting her mourn and other things but it didn't do any good. I feel so lost, I've never lost someone so close to me so suddenly and then to have a friend just completely abandon you, it feels like my world is spinning out of control and I can't stop it. I feel a hole in my heart that will never be filled, I feel like I failed her because of the things that happened with Tk. What do I do in this situation? How do I fix this?