1. Girl, if you're sexually active and your period is LATE, it probably means it moved a week ahead. Your period changes when you're more active than usual and that's completely normal. If you stress, your period will not come. If you keep taking pregnancy tests, YOUR PERIOD WILL DEFINITELY NOT COME! because your stress levels are SUPER HIGH. Take a chill pill! Lay down and get on your social media or watch a movie. Give your body time to work it's magic. 

2. If you're getting 2 periods in one month or not getting your period in a month, it's probably cause your uterus is super stubborn. It is common for young ladies to have abnormal periods! I am one that has them. It is just your body working. 

3. If you're cramping very badly, take some advil. If you feel like your vagina is going to crumble  into pieces and fall from your body, take some advil. If you have a headache that is killing you, TAKE SOME ADVIL.