Hi there and welcome.
Well, they say, "confession is good for the soul." And that is what you have done here today.
Have you also done the same to the gal you hurt? Confessed your wrong to her and apologized and sought her forgivness? She may not, for a while, but ask.
You will heal from this and, you will learn from it; learn appreciation for others; for your relationships.
Sounds like it was a process to hold up a mirror to you. The wise person will come away from this and understand what not to do, in the future.
What you are feeling now is regret and sorrow for many different aspects of your actions. These feelings will soften as time passes.
It won't be easy but, "swallow your pride," seek her out and tell her of your discoveries and that you are torn up because of it. Mend your bridges and you will feel better.
Good luck and keep us posted.