Glad to hear that you are staying physically active! Playing sports and having your period can definitely go hand in hand. Women/girls who are physically active actually tolerate their periods better than those who are not. While growing up, I participated in gymnastics, cheerleading, dance, volleyball and ran track, so I remember that I sometimes it took a little extra planning while on my period to make sure that I had the right “gear”. Consider what you will be wearing, how long you will be gone from home, and what type of restroom facilities will be available. If you prefer wearing pads, make sure your underwear fit well, and use a pad with good coverage. If tampons are your fav, make sure to wear the right absorbency and change as directed. There were times I remember wearing both so when my activity was over and it was time to just hang out, I could remove the tampon and still have a fresh pad ready to go. You might want to pack a small bag with extras (underwear, pads, tampons) and keep some hand sanitizer and a small package of wipes readily available in case the restroom that is provided is not well stocked.
It’s absolutely NOT bad to play sports while on your period. Sometimes physical activity can even make you feel better, especially if you’re feeling crampy or bloated.
As for pad or tampon, that is determined by what makes you feel the most comfortable. In my personal experience, using a tampon while doing physical activity is the most comfortable because sometimes pads will “adjust” themselves when you’re bending and stretching a lot. Of course, pads are much smaller and more comfortable than they were when I was a teenager. So you have lots of options. The key is to work out what works for YOU.
It's totally not bad! Actually, it can be really good, for both you and your cramps. See for more info on exercising during your period. In terms of the old pad or tampon debate, the answer is always whichever you feel most comfortable with. Yes, tampons might be a safe bet if you're constantly in motion, but with all the fancy new pad technology available today, pads are fine, too! You could experiment with both to see which one works best for you. As we know, period care is a really personal thing and what works for me might not work for you and vice versa.