Hi blackbird,
It will take some time for a new mattress to “break in” and for you to adjust to the feel of a new mattress so the first step is to always give a mattress some time before you evaluate it. The Cloud Luxe in the store would have already been broken in so it would also be different from a new Cloud Luxe. There is more about this and some of the additional factors that can affect how a new memory foam mattress feels and performs in post #2 here.
It may also be a good idea to try your mattress on the floor just in case the foundation is contributing to any difference you feel (the Tempurpedic mattresses use a very firm MDF foundation with a solid surface and a foundation can affect how a mattress feels) and some of the other suggestions there can make a difference as well.
There is also more about the different ways that one mattress may “match” another one in post #9 here and while the softness of the 13" dreamfoam will be similar to the Cloud Luxe (most people that have purchased it have said it’s just slightly firmer) and the quality of the materials are also similar as well, the “feel” will be different because of the differences between different types of memory foam.
I hope you have the chance to provide some additional feedback in a few more weeks which can make a difference in how any new mattress will feel and perform for you.
Thanks for the feedback.
Phoenix