late period

my period is 5 days late, haven’t been sexually active in months. I always start cramping a week before up until the day it comes and that’s what happen except it didn’t come and I stopped cramping 😭 i’ve also never had an irregular period like EVER, they’re always on time. i’m trying not to stress because I know that could be a factor but what should I do??? wait and see or go to a doctor??? i’ve also been having very bad lower back pain