I will be perfectly fine then out of nowhere sadness will hit and i will cry then when i stop crying everything is okay again.

Seek counseling: Please seek counseling from a psychiatrist so that if need be, you could get prescription for medication. You may be suffering from depression, and it is an illness like other illness. It is not a moral failing. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, low fat milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex. Get HPV vaccine.