This is a very, very common situation,
Chances are the dentures you had previously were many years old, and for several reasons needed to be replaced, or you may have had other dental issues needing treatment resulting in you needing new dentures or new partials.
Either way, appearances are important and your concern is real and valid.  If your dentures were very old they may not have provided you with the support needed for your lips, cheeks and other areas normally supported by dentures.  Then, when you received your new dentures, your practitioner added this support on your dentures, making them thicker and/or larger in areas.  This new support may be needed, but it can always be reduced somewhat to make you more comfortable.  Many people, such as your family and friends will immediately notice if they see something different in you when you have new dentures.  Many times if asked, they will say will say you don’t look like they always remembered you do, but look better. The new and improved you.
Having said that, sometimes the new changes can be too extreme resulting in an appearance that both you and your friends, family do not like.  You need to talk with your practitioner about this.  An easy way to avoid this situation is to not just show you but have you wear your new dentures while they are still being made so you and family can see what you will eventually look like with them, and if there are still adjustment to be made later, they generally are not big ones, and the displeasure you will feel can be greatly reduced.
As I said earlier,  appearances are important to all of us, and as a patient you deserve to be treated with respect and when you leave your with your new dentures, you should feel confident that your look is suited to you in a positive way.
all my best,