Oooh that's a good sign actually, as you do get a hungry feeling when pregnant, (it is about 1 hrly too!) but actually as long as something is always in your tum, it's happy, it's like it's not real hunger, but a hungry bordering on ickky feeling esp after week 8 of preg onwards.
Fingers crossed it's a good sign for you, but to stop piling on lbs while your body kids you that it's starving -try grabbing bits of chopped fruit or veg eg carrot, celery, grapes and cheese chunks (the cheese actually keeps off the hungry rumble longer!!). (have a ready shopped box of them or you won't do it!)