Wow I cant suck in my stomach?

I know that I may b pregnant bec Ive only been spotting for the past 3 months although I took hpt 3 weeks ago and it was negative in my mind I think I m...and I just saw someone post this that you cant suck inyour stomach when you r pregnant......Does this mean that Im ?i never had a problem sucking it in before and it s weird that I cant do it now... I better go get another test tomrw. What you think?