There is a lot of work for the petite model if you open your mind and stick to your focus. Get over that you wont be a tall Giraffe/model/ and you wont ever rock the runway for Gucci. Accept that you could become Gucci's hand model or shoe model but accept the areas you really should pursue and chase.
It is frustrating to have to settle and know/focus what you are best for, but sometimes getting in the door at an agency for one thing can lead to others. If you submit yourself to an agency as a great model with greay body parts, or eyes, or energy, you might get in the door, and then once you book a job, you might be considered for the other areas in the agency...such as more print work or commercial work.
Talent agencies are also great. They accept shorter models. The best thing to do is keep submitting to these agencies, and keep shooting with quality photographers. Don't forget to submit to the smaller agencies too. You will get into the door, it just might not be the door you hoped for at first...but soon the other bigger agencies and jobs will come.