My closest friends stopped talking to me

In the past, I experienced a sudden loss of communication with three of my closest friends. It happened in quick succession, and it's concerning that none of them are friends with each other. I can't help but wonder if I'm the reason for this sudden change.

Despite my best efforts to keep in touch, such as sending them birthday texts once a year, I never receive a response. It's frustrating because I know people who still talk to them and have their numbers. I'm certain they haven't changed their numbers or anything.

Whenever I come across their social media posts or old pictures of us together, it triggers negative emotions in me. I feel angry, self-conscious, and depressed. I'm not sure what to do. Is there any chance of rekindling our friendship, or should I accept that it's a lost cause?