Land contract

I sold my house in 2016 land contract when move from mi to ok at 4% it was 14.5k land contract to and investment. I was kind nervous at time. So end selling the land contract to listing agent for 11k. After some lawyer fees, I feel rip off. I keep kicking my self. I wish would keep it it would been with risk. Is there any thing bcan do to reverse this. I been beating my self up over this.