Well, doll, it sounds to me like you found yourself a nice gal & just didn't appreciate her enough. Seems that's what she thinks also. That's too bad.
The regret you feel is natural. Its a case of 'not realizing what you had until its gone'. Some ppl need a wake call like this to change their ways. She's probably a lost cause to you, but hopefully you do different with the next gal. All the best.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh