Others' happiness is annoying to me...

When people on Facebook post they are engaged or married or anything good happens in their lives, I get really annoyed. I dont understand why I feel that way. Especially since most of them are decently close friends. I want to be able to celebrate with them and genuinely be happy for them. It's strange.

Any ideas on the source of this?

I have anxiety and depression..misdiagnosed for years as bipolar.

I developed PTSD a few years back.