3 months no period

Im 16 years old and started my period this year. I havent had my period since july

I had unprotected sex in august and have taken 3 pregnancy tests which have all come back negative

I have sore boobs (but they are always sore), egg white/light white distcharge and had spotting once for 3 days at the end of august when my period was due which was accompanied by cramps.

Do you think im pregnant or my body is just adjusting to getting a period