You haven't let anyone down, it takes guts to be here and be honest. I understand what you mean about being ok taking care of other people but finding it hard to find someone to go to when you need help.
I think alcohol used to help me bridge the gap between the capable illusion I imagined I presented and the hot mess I was underneath. I think that is why so much has to change apart from just quitting drinking, some relationships need to rebuilt and some don't work anymore. I have made it a point to try to be authentic as much as possible, learning to say no is hard, but the short term anxiety is bearable, much more bearable to the long term angst and resentment that come from being drained.
And I do believe we often indicate to others how to treat us. I think that you have realized something very important. My old therapist used to tell me that I wasn't being fair to people because I wasn't really giving them a full set of operating instructions.
This may be a short term blip (please make it that), but it is obvious that the wheels are turning and that you are doing a lot of important soul searching. Asking for help here hopefully will be the beginning of a beautiful thing for you!