ugh my belly feels so weird. I'm having contractions that feel like Braxton hicks but they only…

ugh my belly feels so weird. I'm having contractions that feel like Braxton hicks but they only happen when i stand. but as soon as I stand they start immediately. no matter how long or short amount of time I've been sitting. but once I sit they fade away and stop. I've tried timing them standing and one lasted almost five minutes before I got exhausted and had to sit down and then it stopped. this is so weird to me.