Christianity

I performed a sin and even though I felt guilty I did not confess or make good to those I wronged until I absolutely had to.
  
In the wake of this, I don't feel clean of my sin or that there is a way to become clean. I feel that what I have done in repentance doesn't "count" because I didn't initiate it on my own free will like I know should have.
  
It was a thing I promised I wouldn't do, in my mind in a prayer to God, and I broke it and on that basis I fear I will go to hell. I am religious but not a Catholic or part of a family that attends church. Should I seek church where a priest will hear my confession even as an outsider?
  
The idea of confessing in this way seems hollow considering I have confessed to my family, those I wronged, and God in prayer (had to be confronted that way). The person I most directly wronged gave me forgiveness, as well as some of those otherwise affected by it, but the promise I made to God in my head was broken and there is nothing they can do for that even if they wanted, it's a private betrayal between the Lord and I.
  
Is there anything I can do? It follows that the answer is to live well and accept my guilt for the past... but this is ALWAYS true as far as I understand. It doesn't feel right that despite having an intolerable sin weighing down on me I would pursue forgiveness from God on a basis of "Whoopsie daisy, guess Ill just go on and try better"
  
What can I actively DO?
  
I have a hard time imagining hearing a priest say I'm forgiven isn't just human comfort. I don't feel secure in taking someone's word for it. I have never related as a Catholic, I have always felt a person's relationship with God is direct. And I feel I violated that in horrifically direct way.
  
What is the best way to repent for a promise you broke to God? Any help is appreciated. If you think I will go to hell, idk how much functional good it will do me to hear it. That is why I ask for advice. I want to focus on how to move forward.