I am blatantly a paranoid person when it comes to health related issues so I am probably over reacting...

I am 28 weeks and can't decide if I am having braxton hicks, real contractions, gas pains or if my uterus is just stretching. Three times in forty minutes I had an uncomfortable feeling in my lower belly- like pubic line, once extending up to my navel. It feels more like stretching than cramps but intense enough that I stopped walking for a second. I drank a bunch and sat for 2 hours and was fine. Then I had two more episodes of this when I was walking again. TMI- I have had some gas but nothing crazy, I also went number 2 3 times today which is like a pregnancy record because I am on zofran. Baby is moving, I am drinking water and laying on my left side. My lower belly feels sort of tender. Should I be concerned? I will happily take people telling me I am worrying about nothing .