Have any of you ladies had experience with your belly measuring 3-4 weeks bigger than it should be?…

Have any of you ladies had experience with your belly measuring 3-4 weeks bigger than it should be? I went in today for a routine appointment they have me coming in every two weeks now and I have been measuring about a week bigger the past 2 times however this time it was 3-4 weeks bigger and now I have to go back for an ultrasound to see what's going on. Anyone else have experience with this?