Postpartum belly sagging

6 weeks PP and I am naturally very thin. I've lost all my swelling, have been working out since 3 weeks PP minus abdominal work and probably won't do any of that for awhile, but I still have this sagging/loose belly skin. I'm so disgusted by it. Everything else looks pre pregnancy on me, but that. How long will this take? If ever?! Any suggestions to loose it or decrease it faster?