What Are The Early Signs And Symptoms Of Pregnancy?

Hello, im a 17 year old female and im on the pill ( Rigevidon ) i missed a pill on Friday the 7th Oct. Me and my boyfriend had unprotected sex and he did come inside, i couldnt take the pill in the morning because i had left it too late but i took the other pills as normal. My last pill was Sunday 9th Oct and we had unprotected sex that day aswell. I am now on my 7 day break were i dont take any pills and i should have my peiod, we also had unprotected sex on Wednesday 12th Oct while i was on my 7 day break, and i done some research on the internet and i have red that sperm stays inside you for up to 3 days. When i come on my period i normally have bad period pains, nothing else. the last 2 days i have been getting "the feeling" about being pregnant, my breasts are sore, i have been eating twice the amount of food i normaly eat, i have been feeling very tired and today i have had light brown discharge, but i am due on my period today but i would normaly come on my period on the tuesday night. Do you think i could be pregnant? Or do you think its just my period on its way? What would you surgest? Thanks.