I need some mommy's help please. I think i am pregnate but I don't when to test. With my son i have no symptoms until…

I need some mommy's help please. I think i am pregnate but I don't when to test. With my son i have no symptoms until the day of my pissed period. This time I am having really bad lower back pain, nausea, sick to stomach, lite headed and very dizzy, and super sleepy all the time. I work a full time midnight shift job. When I was pregante with my son i did not work and did not feel any of this until I was over a month pregante. My period is not due until the 18th so a little less then a week away.