I'm sorry you are having a rough day...you are going to have good and bad days as you travel the path. I'm sure you'll be happy when your D returns home.
You really need to try to break the habit of checking his FB page. Many times, what is posted on FB doesn't necessarily mean he's having a good time. It's a place to go to brag and yes, stretch the truth a bit. If he has any inkling that you are checking it, he could very well embellish on what he's posting.
I realize that you are still not up to "full strength" just yet, but you need to find some hobbies to work on. Here are a few examples, a nice quiet walk, a visit to a café and have a cup of coffer or a glass of ice tea and while there, people watch, a visit to the library, I did a lot of jigsaw puzzles when my xh left, a visit to the local nursing home to cheer up some patients, volunteer at a soup kitchen. The list goes on and on, but this will help get you motivated to think of things that you could do in your community at your pace.
Sounds like October is going to a tough month. Keep those expectations to zero because often the MLCer will not recognize those special days and I don't want you to be disappointed if he doesn't. If you don't feel up to going to that event that lasts a few weekends, then don't go. You are the only one that has control over you and what you do w/your life.
I do hope that you get good news from your latest test. Keeping you in my thoughts and prayers.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
