your lizard will be fine. dont do the tums unless you are a pro at turning hard things into powder. Your non D3 calcium will be there soon. a few days with D3 isnt gonna cause any issues. i might suggest that until the non d3 gets there, maybe just dust every other day, or bairly at all. In the wild, a chameleon is not going to get a constant supply of food and some days there isnt sunlight, and some days they dont even get a 1 bug. if you skip a day on food, then use the d3 the next day, and make sure it consumes a bunch of water after the d3 consumption, you will be fine. Its important to keep your lizard healthy, but dont over do it. good luck.