I came inside my girlfriend on her last day of her period what are my odds of her getting pregnant?

Low, not zero: Pregnancy is known to have occurred from sex in any and all days of the cycle. If the sex was within the past 72 hours, your girlfriend may wish to take plan B. If she misses her period by 4-5 days she should do a home pregnancy test. Wish you good health! - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. 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, if you have sex.