What Could Be Causing Persistent Swelling In My Left Leg And Foot After Taking Meloxicam?

In november I took some I believe meloxicam for 2 days for my pain in hip.my left leg and foot swelled up and after an ultra sound which was negative and then went to get xrays on my left foot ,again negative.I still have the swelling and in the morning it is a little better and after I m on it all day ,it gets bad again.my regular physician couldnt figure it out.What do think.My right leg is fine and right foot