History of weird hormones and irregular periods

Sooo I am 22, and I have been off birth control for 3 years. The reason I was on it was because of my irregular periods(I would go up to 6 months of no period then 2-3 weeks of periods) but the reason I had to get off was because I would get chest pains, and even started collapsing. The doctors said it was due to the hormones. Anyways I was wondering could someone be pregnant and a pregnancy test not detect a pregnancy hormone? I am currently one month late from my period start date. And like all women, I get scared I am pregnant every time.