First of all, you've lost 27 pounds in 4 weeks... that's amazing! Thats almost a pound a day! At the risk of sounding insensitive, at your size if you really put in the work that's not something you should be too concerned with... you do have a good bit of extra.
As others have said, the weight loss will likely slow down so hopefully that will asuage some of your fears. It looks like you're eating a nice healthy amount of calories and getting just enough exercise... it's nice to see!
Just remember that as you continue to lose you'll have to adjust your diet and workouts to match your new, smaller frame.
Seriously though, congratulations. That's really inspiring. That's Biggest Loser type numbers and you're doing it on your own!