Ligament injuries. I am suffering a lot!

Hi Sir/Madam , Previously I had a ACL reconstruction in my right knee . Recently I have again injured myself playing but this time the left knee (ACL full tear and PCL partial tear ). And I can feel I am not comfortable with my right knee also . If that was a ligament tear in my right knee also , will it be preferable to go for the surgery (reconstruction)at a single  time for the both legs . Will I be able to recover fast if surgery is done for the both legs  at a single shot . Could you please suggest me on this . And could you also please tell me why these multiple ligament injuries are occurring to me . And my body weight is more , is that really causing these injuries . Tips if any so as to get rid of these injuries . For simple things I am suffering a lot Thanks and Regards Pradeep