I'm 14, missed my period by 15 days. I hit my stomach pretty hard and now there's balls of blood. This happened before but only for a few minutes. It's been 2 days. Can I die from blood loss and will this go away on its own?

You are not bleeding. Really. You are not bleeding. Keep telling yourself that. All the fluid that leaves your body during your period was gathered in the lining of the uterus two weeks or so before. It (and there's more than just blood) lines the inside of the uterus in case a fertilized egg moves from the Fallopian tubes into the uterus. It's there to feed the baby. If there is no fertilized egg, the lining will detach from the uterine walls and leave through the cervix then the vagina. You only lose a couple of teaspoons of fluid. It takes longer because YOU ARE NOT ACTIVELY BLEEDING. It's just seeping out of its own accord. It won't help anything if you punch yourself. Try to educate yourself on your own body. It's pretty amazing.

Can oxygen burn?

As burning is the process of combining with oxygen, it is definitionally impossible for oxygen to "burn".  Although I haven't done the math on it to confirm it, I doubt that oxygen will spontaneously combine with fluorine to form oxygen difluoride in significant quantities, as the latter compound is fairly unstable and dissociates into its constituents at

What is the most effective way to train for pull-ups?

Stuff the gym, get a pullup bar at home. Either buy one of those door frame pullup bars, or find a beam on the roof or in the shed, or tie some ropes to a tree with a metal bar at the end. What you need to do is "try" to do as many

Should I continue this long distance relationship?

Online relationships should be temporary. You might meet online, chat for awhile, find you are both interested, then you meet in person. Otherwise, it is a fantasy at best, and a dangerous scam at worst.If you and your online friend decide to meet, that is the time