Advice pleaseeee

Okay guys.. I’m not sure exactly where this belongs, but I’m just gonna shot for it and post it here. I usually start my period on the 27th, but the cramps&back; pains start the 25-26. I haven’t had any back pain or stomach cramps. I’m 3 days late which isn’t usual. My period is ALWAYS on time. Could I be pregnant, and if so, is it safe for me to go on vacation? I’m suppose to leave Monday night.