Hello, I m 18 years old. I first got my period when I was 13, and since then my periods have been fairly regular, always falling between 3 and a half weeks to 4 and a half weeks. My last three periods have been only 2 weeks apart. I haven t noticed any significant change in the heaviness or length of the period. I usually have a small amount of white/yellowish discharge but in the days leading up to my last period it turned brownish in colour. I am sexually active although I haven t had sex in the last few months. The only thing I have noticed is that I switched from using towels to using tampons exactly before my periods became irregular. Could this be related? What else could cause it?