Hi there -- Thanks for your question. That definitely does not sound normal. Although we have never directly tested a Zinus mattress, I can say that in the many, many dozens of mattresses that we have opened in our testing, we have never encountered anything like that. IIRC, the longest period we've seen for a mattress to take on its full and final shape has been about 24 hours.

Base on that, my initial instinct is that you got a bum mattress and that you should be looking to contact the company and/or the retailer who sold it to you to see what remedies you have available to you.

Beyond that, I do think it bears mentioning for the benefit of other readers that not all online mattresses are created equal. On some level, you do get what you pay for, and this particular mattress is a very low-priced option that is made in China. Such mattresses are shipped across the Pacific to get here, and stored in warehouses for an unknown amount of time along the way. All of this could certainly have something to do with how long it is taking to expand as well.

I hope that's helpful.