Pregnancy test question

Has anyone ever experienced having no period but getting consistently a negative result when peeing on a pregnancy stick?

It’s been six days since my period was supposed to start and I’ve taken four different pregnancy tests and all have turned up negative. Tried taking them at different times of the day, tried the same brands as well as different brands, taken them throughout my six days of a no show period and NOTHING.

My weight is good, I had a baby two years ago but I don’t feel any hormonal differences. I still make a little bit of breastmilk, less than an oz. and sometimes my son will ask for “booby time” but rarely ever. I did experience a lot of stress the last week but I didn’t think it was anything I couldn’t handle. Anyway, weird. No pain. I feel like I could be pregnant but I’m just thrown off by the negative results…