A good IC can help you free yourself of the guilt. You have not failed, it is not your fault; you have poured your love out. Forgive your errors in the past as none of us are perfect.
As for the rest....yes, your DDay was over a year ago, but your limbo has been much more drawn out, and the D process is new to you with all the heartbreak it entails. So, don't blame yourself for not being further out. You have had a lot to contend with.
I have no new suggestions, just the usual: rely on friends and family IRL for support, to vent or to distract yourself, try and find new areas you want to pursue as a hobby or skill, exercise, eat right, take care of yourself, maybe try reading a book such as Journey from Abandonment to Healing. Be kind to yourself.
And maybe, just maybe, stop fighting back the tears when they come. Let yourself cry when you need to. The tears will pass if you let them come, and are part of your body processing this trauma.