So hungry!!

I am five weeks pregnant with my first and I can't believe how hungry I am!!! I read that you don't need to eat more until later in your pregnancy but I  always hungry right now and want to eat!! It is so hard not to! It's frustrating because I have lost 40 pounds recently and I am thrilled to be pregnant but i really don't want to gain back a lot of weight! I am trying to continue losing if I can! I am trying to eat healthy and I am still exercising every morning like I was before getting pregnant!