Am i pregnant?

I'm sixteen. I had unprotected sex 3 days ago with my boyfriend, the day after my period was due I had a bit of blood in my knickers but normaly im heavy and this wasn't, it seemed different. It was a lot lighter and a browny colour. My appitite is still...

more or less the same and im not expiriencing any pain. I was thinking maybe the slight browny blood, could be implantation bleeding, what do you think?
Do you think im pregnant?

Wait until you miss your next period then take a test..how are we meant to know if you are or not? Or go to the doctors..but it's to early atm.

If you had unprotected sex with your boyfriend then yes you could be pregnant. Irregularity in the periods is a big sign( *if* the periods are usually very regular and on time). Take a test in about 2 weeks, if you take it before the hormones levels will not be high enough and may indicate a false result.