Is it true with each pregnancy you get bigger?

ok im pregnant for the fourth time, im only 5 weeks. but today i was getting ready to take my other kids to see santa and i could bearly on my jeans that just last week fit fine. i dont remember bein like this so early on with my other ones. so is it tru that with each pregnancy you get bigger? also with each one do you start to show sooner? please any anwers well ease my mind!! thanks!!