I found a pair of pants on sale this week. I bought them in my regular size, and they seemed to fit. I tried on a size smaller and they were slightly tight. So today, I put on the pants, and after a few hours of breaking them in, they are FALLING OFF ME. And I am seriously ticked about this. I should be happy, that I may be going down in a size soon...but no, mad at the work of taking them back.
The pants probably have lycra in them or something similar. If it's over 2% it will usually have a tendency to expand by over half an inch plus with normal wear during the day. Take them back and get the smaller size. Wear it around the house and it will fit
I hate taking anything back for returns, but better to have to take the pants back because they are too big than to have to return them because they're too small. Be glad!
They often cut trousers disregarding the grain so that they can get as many pairs as possible out of whatever fabric and then they'll stretch out really fast. I've had trousers where the knees stretched out loads from sitting down.. eugh. It's great that you'll go down a size though! way to go!