I drank beer from same glass with my friend two weeks ago, and week after that her boyfriend realized he has mononucleosis. she didn't yet. will i?

Not necessarily: Most adult have had infection with the virus that causes mono and you may have had that be already immune. You could get a blood test to see if you have antibodies to EBV which would indicate if you were infected with the virus. 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.