I overthink a lot & need help how to overcome over it.

I don't know my friends say I overthink alot and even I get it and my day goes off bad when even when I distract my self in my office work it doesn't affect my work but due to a girl I keep thinking about the hurt I have given her and her reactions and actions make me feel I did something wrong again & that get stuck in my mind and overthink over it and I have confessed her my feelings but she doesn't say much about it like she says she had a crush over me at the beginning but later all the activities happened after the past days she says I am neutral now so to get that validation or approval from her I keep on conversing with her even in my work time for 1-2 hours even when my colleague or boss watchs me I make time for her in my work time also but still I get upset that she doesn't get or understand me and says about herself and sarrows only but I am fine with that listening to her everytime but even I feel to be heard once atleast and need some word of mouth that your doing amazing or good that I am here but that the one thing I am feeling right now to hear but I am losing my head over it.....