I haven't had my period in 2 months, and my urine test came out negative for pregnancy. Is there anything else that can cause your period to stop?

Yes. Many things can cause you to miss a period. Common causes include emotional stress, recent illness, weight loss, and excessive exercise. There are a number of uncommon causes as well. Consider the above etiologies. If your period does not return in the next 1-2 months, then consult your doctor.
Yes, Many things. Most commonly, it may be due to dieting and a lot of exercise. See your doctor for evaluation and blood tests.