Period

My period skips around so much I never know if I should take a pregnancy test or not. Sometimes I completely skip a month and other times I only have a period every three months. But lately I’ve been feeling sick not sure if I’m pregnant or just a cold. Not throwing up just nauseous. And my lower back hurts like I’m gonna get a period but it doesn’t come. I’m almost 7 days late for my period. Last period 24-31st of December. I really don’t want to go back to birth control bc it made my moods really bad and made me emotionally exhausted any idea what I should do? And when/if I should take a pregnancy test