I'm 16 and Im worried I might be pregnant. My period always varies from month to month but this time, I found a brown discharge I usually find before my period starts. Only this time, my period never came. I have backaches and my tummy is bloated. Could it be implantation bleeding or just period irregularity because im still young?

Your information is not sufficient dear, When was your LMP.. Did you have unprotected sex.. How long after the discharge do you usually get your periods?
Since you have irregular periods, why don't you just take a HPT instead of worrying?

My LMP was 19th October.. and yes I had unprotected sex. Usually I get the discharge a day before my period..

I would suggest a home pregnancy test at this point.

A missing period, especially at your age, could be due to being so young. It can also be due to unprotected sex.

If you continue having unprotected sex, prepare your body for baby with prenatal vitamins and possible STDs. I would take the abstinence route or at minimum use birth control + condoms if I were you...

HPT as soon as possible,, and I agree with LearningAsIGo... use a condom at least. You don't want to be a mother at this age, do you?