Give yourself time!
When you press the brake in your car, it takes time to come to a complete stop. The same is true when you try to go from losing to maintaining. It's hard to know immediately if you are eating the right amount, especially with a significant amount of exercise like you're doing.
As you are learning, you've got to EAT to fuel that level of activity and it can be stressful for us formerly fat people to eat at levels that at one time would have led to weight gain.
Track things for a month or so and see where you end up. If you continue to lose, then you obviously need to eat even more. If you seem to be maintaining within a few pounds (keeping in mind normal fluctuations), you're probably where you need to be. If, heaven forbid, you do start to gain again, just ease off a tiny bit on the calories and you'll stabilize.
Whatever you do, don't stress it, because you now have all the knowledge and tools to stay at the weight you want!