Fox Float RP2 rear shock problem - soft run and hiss sound on first 5-10% of travel
It might not be possible to give you a 100% answer without opening the shock, but it certainly needs service.

6 months of use isn't a great determining factor for service intervals, hours of riding and type of riding (how big, how dirty) are much more important. Have you rebuilt your air can yet? Do you know how many hours you have on the shock?

You can probably run it for a bit (until winter), but it may or may not make it. Either way, the shock needs rebuilt. Sorry dude.