Am I Pregnant. PLEASE HELP

I am a 17 year old teen who has missed her period by 3-4 days. My period is usually on time but I have missed my period before but for 2 days. I am sexually active. My partner and I use a condom and before he ejaculates he pulls out with the condom on.

I've been stressed this past month and been working out mostly on my lower body. Could I be pregnant or could this be something else?