Since then, I have been dealing with so much anxiety and anger toward myself for flushing 6 months down the drain in one hour.
when these things happen, and when they happened to me, i found it best to use them as a gauge for where i was at in my detachment process.
you havent flushed 6 months down the drain. it has however, revealed that you have some ways to go in your detachment process.
the bottom line is that no contact is not a substitute for detaching and healing. its a tool in order to get the space to do so. that will fail if you hold out hope, if its a means of garnering contact, or if you want to get a message across.
why did she quit responding? because the two of you are broken up, and shes further along in accepting that the same old fights died when the relationship did. you havent entirely resolved those issues; i hadnt either at the same point in my detaching process, but ultimately, i had to resolve those things myself, and with help here. it wasnt going to come from my ex, who had a very different perspective than i did.
my advice? dig in, dont ditch your support group. you dont have to wing it or do this alone. embrace the idea that this wasnt something that threw away all your work - if the relationship is over, its less about no contact, and more about moving on, right - and that it was something that told you that theres more work ahead of you in terms of detaching.