Nervous & Could I Become Pregnant

I'm Very Nervous And I Think I Might Be Pregnant I'm Not For Sure But Think It May Be A Possibility My Period Came On August 11th And It Went Off August 13 Well I Had Unprotected Sex On The 21 Which Was The First Day Around My Fertile Window We Had Sex 3 Times That All 3 Times He Ejaculated In Me Could I Be Pregnant?