18 Days late!

So I got my period towards the end of April, then I got it again 2 weeks later, I’m not someone who has irregular periods at all, I’ve check my logs and I’ve always had gotten my period on the estimated times, I’m late by 18 days now, took at home test came out negative, I’ve been having brown discharge, light cramps, nausea, breast are perky, today the bleeding did get a bit heavier however the blood flow is dark red with some brown.. should I take another test? Or what lol I’m so confused, I made a doctor’s appointment but I’m still concerned..