Hi I've Been Having Some Issues But Didn't Think It

Hi I've been having some issues but didn't think it was worth going to waste a doctors time, I've been having really itchy and sore nipples for about 4 days, I've had swift sharp cramping and a few other unusual symptoms, I'm not due for my period for another week and took a pregnancy test 2 days ago and came up negative, could it be anything else or should I test again when I'm due? I have never experienced these before even when my period has been due, thanks x