Looks like someone put aftermarket springs on the rear...
take it to a spring shop and have the de-arch the rear
of the springs... the front of the spring should be
fairly flat... thats the part that holds the axle in
place and gives you the lift to plant the tire... the
rear section is your spring and gives you the ride
height.... or you could add lowering blocks... I
prefer to de-arch them...... this is assuming that
you arent sitting on bottomed out shocks... quick
check... unbolt the bottom of the shocks and pull
them off the mounts
EDIT
also check that your shackles are not messed up
(bottomed out or wrong angle)