Hi, I am Dr. Girish, Orthopod
Yours is a case of Internal derangement of Knee. there are six ligaments in and around each knee and by your history, I strongly feel you could have injured your ACL(Ligament connecting thigh bone to leg bone) /+ Menisci (cushion between knees).
Treatment: YOu need quadriceps strengthening excercises and knee bending excercises apart from anti-inflammatory medicines at present. walking can be done with knee brace
on and after 3-4 weeks of injury
the knee will be examined again and if need MRI
of the knee will be done for confirmation of the diagnosis and if ligament is injured you may need Arthroscopic surgery