Mesentric LN can be enlarged due to infection or inflammation, local or general.
common cause of mesentric lymphadinitis is viral but other infection may too cause enlargement, including cancerous tumours.
you had US done, i suppose ,to be told that you had LN enlargement.?
Tuberculosis is also one of the cause.
Next Steps
consult a physician in your city.
get CBC ,urine examination done.
you can consult via online chat too to know more details before you see a physician.