Do I address it with my good friend or just move on?

A good friend of mine got married recently and did not invite me to the wedding or any of the festivities. She is friends with both my husband and me, so it seemed extra strange that we would have been left out. As it turned out, it was a destination wedding, which we would not have been able to attend both for financial reasons of taking a trip while my husband is out of work, but the bigger issue is that I have myalgic encephalomyelitis, an autoimmune disease which causes chronic pain and exhaustion. I have had M.E. for over ten years, longer than we have known each other, so its always been in the background of our friendship. It does hamper my life considerably; not only can I not work a regular job, I can very rarely attend most social functions, including the numerous dance performances that my friend takes part in. I think she knows that it kills me that I cant go to them and would absolutely be there if I could.

Weve been through a lot together and I thought we were extremely close, (like sharing intimate secrets, shes napped on my bed, in my PJs) although when my best-friend-soulmate-dog was dying a few months ago, I barely got any response from her about it. I messaged her that my dog was dying and all she said was, Oh no, poor baby. Other friends were checking in regularly to make sure I hadnt given up on living, but I only got one message from her ever after the fact about what a good life my dog had had. And maybe she was busy with wedding things, but I was very hurt that she was so distant while my life and soul were being shattered... but she had also adored my dog. Maybe shes offended that Ive never been able to go to her dances? Or Ive done something else? I dont know, Ive been searching my mind and cant think of anything... it seems odd if she would take my illness personally when its been part of our friendship the whole time. Maybe they could only invite a small number, maybe she assumed (correctly) that I wouldnt be able to go, therefore, why bother invite me at all? Shes generally pretty considerate though and all it would have taken was a text saying, Id like to invite you, but I cant, sorry! and I wouldnt be feeling this way (about the wedding anyway, the dog is still a painful thing to think about). Im feeling extra salt in the wound right now as my social feeds are full of everything wedding all the time from her, and Im still trying to convince myself that life is worth living without my dog (and yes, I have a therapist, but 45 minutes every other week is not enough time to discuss all my problems in so I havent even had a chance to ask her about this particular facet of pain).

So, do I ask her whats up, tell her I was hurt by her not even trying to include me in such an important moment in her life, and also her distance while my dog was dying? Will that help things or just make the rift worse? Im extremely non-confrontational; shes slightly better at it but also avoids it when possible. I dont want to lose the years of friendship we had... or maybe we were just never as close from her side as I thought we were? Does this ever actually work to repair a friendship, or would I be just as well off writing a letter that I never sent? Any advice on how to handle this would be really appreciated! Thanks!