Some people won't ever make it over the 'hump'. I had morning sickenss until about 16 weeks, and then it returned in the third trimester.
As long as you aren't vomiting and becoming dehydrated, then there isn't anything wrong. If you are being weighed frequently, you can tell if your baby is gaining weight appropriately.
I was worried just because I only got hungry in the third trimester, when my baby really packed on the kilos. But it's pretty obvious when your baby isn't thriving, you'll be able to tell if you aren't putting on enough weight.
Just make sure that everything you do put in your mouth, is the best thing available, make every bite count!!