You are up against the classic problem of making bows.
Consider yourself lucky that you have no power tools, as you would have ruined it by now.
Sometimes it does go slow, but you only learn how much wood you dare remove by experience, and generally the point where you think "damn, nothing is happening, I need to take more off" is exactly the point you need to be slowing down!
Be sure to flex the bow plenty to let it settle, check the thickness of the limb is being reduced in an even taper. remember that a few rasp strokes at mid limb will make more difference that the same amount near the grip.
Try measuring the thickness every 6" along each limb with a pair of vernier calipers, it may give you some idea of what's going on. (Even the digital ones are quite cheap these days... and they don't count as power tools, so it's not cheating
)
What weight are you pulling it back to? How far? and like the others say, we need the pics!
Bottom line is, it's not a race!
Good luck.
Del