I hate it when that happens. I can tell you're frustrated and I don't blame you a bit; it's enough to drive anyone up a wall.
If you lost three inches, it's very likely that you've lost fat
even though you haven't lost weight
. The scale only measures how gravity affects you--all of you--not how much fat you may have lost. You could be carrying around extra weight in the form of water or yesterday's dinner that's still being processed. Maybe you've eaten a lot of sodium lately, maybe it's near That Time, maybe you gain a pound or so in water weight when you ovulate.
In other words, SO many things can cause weight fluctuations that aren't fat fluctuations that it's hard to say anything is "wrong."
On the other hand, the fact that you've been in the same ten-pound range for the last year does sound like a lengthier stall. What is your daily caloric intake? It might be time to step it down a little bit; a lot of us have to do that as we slim down.
If you're already at a pretty low number, it might be time to re-check your weights and measurements, as Gale02 suggested. You might be suffering the side effects of "portion creep" if you've decided to lay off the food scale and measuring cups.
You could also try giving your metabolism a shake. Try calorie cycling to see if that un-sticks your stuck weight. Some people switch plans altogether and go low-carb for a month or two to see how they feel.
Chances are you don't need to do anything drastic, though. Three lost inches says you're not doing anything wrong, and while scales don't lie, they also don't tell the whole truth about how much fat you've lost. That's one of the reasons I weigh daily even though I used to dread it--it helps me put the scale back in proportion.
I'm sorry you're frustrated and I hope that it changes soon.