false negative?

okay I have a stupid question I know its possible to bleed/"have periods" while pregnant and not know it. but heres the story, I had my daughter 3 months ago, my boyfriend and I have had sex lots of times, many times while ovulating. I took a pregnancy test 2 days ago it first appeared positive then turned negative. I took one again this morning and same thing happen. could be be a false negative? I feel like shit like I did when I was first pregnant with my daughter, in super crampy nauseas, emotional, moody, always tired. is it possible I'm pregnant? I don't know what to do.