Maybe you need to up your exercise?  Include some strength training so that you can build muscle, which in turn will rev up your metabolism and get you over your plateau.  I wish I had the problem of no appetite!!!  Does your lack of appetite seem normal to you, or do you think you should get checked out by a doctor?  Also, maybe you're not getting enough calories, which could slow down metabolism...check out some protein powders out on the market, they are called "weight gainers" probably because they are high in calories.  This way you can get enough calories in for the day, and it would just be a small drink, you don't have to force yourself to eat so much.