pregnant ?

i am irregular when it comes to my period. according to <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> i was due for a period 12 days ago. i had sex on the 18th, which i was five days “late” already. i’m taking a test on monday to be sure but i started getting dizzy today. should i be concerned ?