This is an unfortunate question,  it is common, but shouldn’t be normal.
If your new dentures are made well they shouldn’t be very loose. There are many different situations and conditions which dictate looseness and fit of dentures, but having said that, they should fit well, and preferably without the use of adhesives.
There are medical conditions which will never allow dentures to be tight, and if they exist in your case, you must be made aware of them before you start your new dentures.
But for the majority new denture should be well fitted and allow you to carry on with your daily living without them constantly dislodging and causing you pain.
After an agreed amount of time where your dentures will settle into place,  if they are still loose, you should communicate this to your practitioner, because they will rarely become tighter, and will cause continuous discomfort, resulting in you not wanting to eat, and not feeling well in general.
Your practitioner should do everything at his disposal to remedy this and provide you with the best fit possible for your new dentures.
Thank you,