Am I the only one?!Need some opinions!

Today my AF is five days late but I've taken three tests. One two days before. One on the 14th(day of missed AF) and one last night. All of them have come back BFN's. I'm also 16dpo. My period is always very regular so this is very strange for me. I've been checking my cervix and it feels different everyday. Plus I'm very gassy, had cramping on Monday and Tuesday. Nausea ocasionally. And very sleepy. Has this happened to anyone else? Do you think there's a chance I am pregnant?