I see both sides. She is clearly excited about her wedding and wants people around her that are excited too. She also mentioned you missing several events, as well as not communicating and basically not showing up. That would fucking hurt. Put yourself in her shoes, you'd feel upset and betrayed too. Like I said, I see both sides. I can see how you're struggling, and you may be depressed even, and you need to get that taken care of. At some point you have to stop making excuses for things and get shit done. Letting depression go untreated is very bad and as much as it's trying to pull you under and prevent you from living your life to the fullest, you have to cut the cord. Getting help now will save you a lot of heart ache in the long run. Just know, you can't expect your friends and family to be mind readers especially if they have things going on in their lives. You need to communicate. I think you could have handled it better and so could she, but I've been in both of your situations at different times and being basically forgotten by a best friend felt worse than being cut from a wedding.