We will need more information i reckon
Did you land on one leg or two, with the hip turned or straight compared to the body and if so which way - paint me a picture!!
Any excessive back pain at all with any movement or if you dig your fingers in anywhere?
Have you continued playing or have you rested completely? 6 weeks at your age should sort out most muscle pulls 70-80 percent better.
The answers to these questions are my food, so feed me.
You could try a few simple tests to help here
a) lay on front and pull heel towards buttock, using you other heel around the shin to add pressure - any pain? Now push your shin into your heel as if trying to straighten the leg - any pain or pain increases?
b) Lay on back and pull knee towards chest - any pain? hold this position and now push you knee accross the body - any pain or pain increases?
Only two very very very basic tests but might help to get the ball rolling.