What is wrong with my Bearded Dragon?

What's wrong with my bearded dragon?

• I have a 4 y/o bearded dragon. He lives in a 75 gallon tank with crushed walnut shell substrate. I feed him a diet of Romain lettuce every other day and a dozen crickets every 3 - 4 days. I dust the crickets with calcium powder every time I feed them to him. This diet works out fine for him. Occasionally I will give him broccoli and carrots. He doesn't seem to like fruit. I use a 5 ft florescent tube light and 60 watt day and night bulbs. The lights are roughly 20 in out of the dragon's reach. About 5 days ago, I fed him 2 dozen crickets from the store. I do this every so often if I go longer than 4 days, and it's never bothered him before. I noticed starting the day after I gave him the crickets, he was a really pale yellow color, except his beard and half his tail from the tip were black. That day he had a good sized poo but it was runny. Since then, he has pooped a few times, but they were considerably smaller than normal, and most of them (not all) have been just as runny. Yesterday morning, he actually threw up, but he didn't seem to feel any better. Sometimes, his color will darken slightly for short periods of time, but even then, he's still really pale considering his normal color. I suspect he is impacted, while at the same time, experiencing brumation. I am currently on my way to the vet, but would still appreciate any input or advice anyone may have.

• Answer:

  the vet is your only great source of info. if its impaction make sure to use reptile carpet or calcium sand for his cage.