What does this mean? (females only)?

I have had my period every month except last month, this month i just had my sixteenth birthday. I have my period on the fifteenth of every month than about april I started having it on the 25th of every month. however i was stressed last month and skipped it completely. but this month since my sixteenth birhtday i have been experiencing major stomach and bladder pains, and just a few minutes ago.. i went to the bath room and saw i was bleeding like period but it was very very light colored like almost pink? Is there something wrong with me? Is it a sign that I'm pregnant or have an infection or what?