How do you know that your belly has dropped ?

I am 32+ weeks with second pregnancy ( first pregnancy ended at 24 weeks). I am having a very different feeling since yesterday about my belly. There is a loose fat roll right under the belly where the underwear line goes which wasn’t there before. There is also a very characteristic butt pain in both sides of the butt (apologies for the callous description but I don’t know how else to describe. ) is this belly drop ? Unfortunately I don’t have any previous picture.