My mom didn't even know she was pregnant with me until she swore she felt me moving and got checked out to find she was in her 2nd trimester (I was a tube tied baby that snuck my way into the world). She never had any other symptoms, had light periods her entire pregnancy with me, and she didn't show with me until she was in her 8th month, and only gained 10 lbs with me. She weighed 125 lbs (she's 5'6")I came out 6lbs 7oz and 19.5 in. Had she not had my brother and sister before me and known she felt movement and not gas, she could have easily wound up on an episode of "I didn't know I was pregnant". Try not to worry yourself. Some women can go an entire pregnancy, without any symptoms, feeling fabulous.