Question about sec and TTC

♡Lyrics♡ • 28 have beautiful baby boy name Nova Rayne
I've notice when I have sex without a condom my period is all ways late idk why but is that normal for when it having sex with out using condom or birth control some times I'll be let my whole period then start or sometime it be 2 days late it really confusing for me and my period are regular to there only late if I'm having sex without condoms