is this really happening

My period is now 5 days late, I've taken multiple cheap pregnancy tests and they have all come out negative. My daughter is two months old so what are the chances my periods are still regulating themselves? I have a 2 almost 3 year old and a 2 year old. My husband is deploying next month and I'm really praying I'm not pregnant. I could not imagine being pregnant, taking care of my kids with no help from my husband for 9 months, we used condoms every time we had sex and my appointment to get my IUD is next week! Ahhhh