Generally speaking, it rarely possible that eyelashes grow back. Eyelashes are an important safety system for the eyes. They keep dust from falling into the eye. All human hairs go through three stages: anagen, catagen as well as telogen. In my opinion, you are going through between the anagen phase and the catagen phase. It means you are experience a stage of transition. The eyelash falls out during the two to three weeks, losing an eyelash during this period means that new eyelashes will grow in faster because the growth cycle of the hair was not interrupted. Thus the growing eyelashes seems shorter than other eyelashes which you saw before. It's just a growth cycle of hairs, other than the growing back of eyelashes.
I read online that eyelashes may grow back. And it is also depends on the personal health and diet. And i also saw somebody say that taking more Biotin can help strengthen the body's hair follicles and makes the hair and eyelashes stronger. But sometimes, the losing of the eyelashes means the new eyelashes will grow latter. So, don't worry. If it is really serious, you shall visit an eye doctor.
Your shorter eyelashes may be caused by the bad habits of life, including your diet and rest. Although the eyelashes always grow back, you could do something to make them grow fast. You could apply the vitamin E to make the eyelashes grow better and longer. It really works. You could have a try.