I also hope you don't lose your fish!
This is definitely a hobby for patience, patience, patience.
Even though your LR was cured and active, your sand bed is brand new and hasn't had enough time to build up any of the beneficial bacteria necessary to help keep your tank stable. In a tank with a sand bed, the sand bed will provide an important portion of the filtration in a reef tank.
We also have no idea what sort of filtration you're using or anything else that is going on with this tank.
I think it might be best if you find someone to take the nem, pray that the rest of your fish live, and do some serious research on how to set up a new tank from scratch. It would be even better if you could find someone to hold your fish or return them to the LFS and start over from scratch. The first part of setting up your tank from scratch will include doing a lot more research than it appears you have put into this one. We're here to help you, not bash you, so don't think this is being mean or anything. We just want to help you out so that in 6 months or so you can have a happy and healthy environment for your fishies and nem. It hurts us to watch these beautiful creatures die because of a lack of patience on a hobbyists part and a lack of regard on the part of many LFS's who will sell anything to anyone to make a buck.
I'm setting up a new tank right now myself and even though I'm using live rock from my established 7 year old, 120 gallon tank, I've had just the tank and the rocks and the LR in the filter chamber and a couple of snails running for 5 weeks now alone. The cycle is also where you get used to the ins and outs of running your tank and keeping your parameters steady. I'm at the point now where I am going to add a couple of hardy green chromis fish and a full clean up crew to the 29 and let it keep cycling. It will be at least 6 months before I attempt to add coral or anything other than the hitchhiker GSP's that came in on one of the LR's already.