16 weeks missed period and flutters but negative test

Kala

I’m nearly four months late for my period and I’ve taken 5 at home pregnancy tests that say negative but around the beginning of this week I started to get a spasm in my lower belly on the left side. Since then it’s gotten more frequent. It’s worst after I eat or when I’m really relaxed like watching tv or falling asleep. It has however gotten to the point when I feel it on and off all day and it’s moved places and feels more like tapping from inside now. My boyfriend thinks I’m CRAZY. But I’ve never felt this sensation in my life before. Has anyone else experienced this? Were you pregnant? If not what was going on?