helppp

i had sex with my boyfriend last week and i was supposed to get my period 4 days after but i am now 3 days late, i am on birth control and he came inside me ik we should’ve been more careful but it just happened and now i’m suuuuuper stressed out and worried this whole month i have been under alot of stress and i recently started working out alot so maybe that could be the cause of being late??? idk if i should get a pregnancy test or just wait /: