I hope this doesn't make you stressed out, but once i went on my period at the end of class for NO REASON! and there was blood on the back of my pants but thankfully, i brought an extra pair of pants. so my advice for you is to always bring an extra pair of pants or something just in case! ( and if it gets on the back of whatever your wearing and you don't have an extra pair of pants, use a jacket to cover it if you have one that day )