am i pregnant ?? please help!

i had unprotected sex on the 22nd of august. i had my last period from the 9th to the 15th of august. it is now October 7th (12:40am)and i have basically missed by period for 2days because it was supposed to come on the 5th. i took 4 pregnancy test (first response) and they all came back negative but i cannot stop worrying about if they are wrong since i haven’t gotten my period. about a week ago i have a lot of white discharge on my underwear but no there is no discharge at all. note; i am very young and if i could be pregnant , what are things i could do ?