Hey, congrats on getting your injectable! Honestly, most doctors say it's best to wait at least 7 days before doing the deed, especially since you just got it today, your body needs time to settle and for the hormone to fully work, plus your period adds another layer na mas okay lang i-wait. I'd suggest texting or calling your OB to confirm since they know exactly what they gave you, pero from what a few of us mums experienced, waiting that first week is worth it para safe and walang worries!