TTC #2 and my LMP started May 14th, why do I feel what I feel?

We've been TTC now since January and I thought this month for sure I was pregnant. My period was 4 days late and normally isn't. It started off really light and then 2 days later it got heavy and just left. Since then I've what I think is "movement". If you've ever been pregnant you know what the beginning movements feel like. Well...that's what I feel. I did take 2 pregnancy tests before I got my period and of course they were negative. But then...why do I have these lil twinges in my lower stomach?