I think I'm crazyyyyy

I had a baby a year ago... and lately I've been feeling movement in my belly... I pass it off as gas or whatever, but just now, it felt like something was pushing out of belly and I could feel it with my hand (the size of my palm almost) and it stayed for a good 10 seconds and then moved away.... I took a pregnancy test 3 days ago and it was negative... I'm probably paranoid or crazy but has anyone ever had or heard of someone with a stealth pregnancy ??