Well, what you describe certainly COULD be related to the drinks you're consuming that have high levels of caffeine. You're describing that caffeine "crash" so many experience, especially the people who regularly ingest significant amounts of energy drink type products.
It sounds like so far, your lab work was all normal, which is good. I think it's more likely that your symptoms are attributed to your caffeine use, versus an adrenal problem. The best way to really figure that out is to do a test run where you eliminate that from your routine completely. I know you did that already, but you didn't give yourself enough time to adjust. You were likely still feeling a "withdrawal" type phenomenon.
If you cut those things out of your diet and give yourself some time, like at least a month or two, you may find that you're feeling much better. I think it's a good idea, it's not the most healthy of habits, and if it's responsible for making you feel lousy, that's not a good thing.
Obviously, if after a month or two without these items you're still feeling lousy, then it's time to go back to the doctor for more testing.
thanks alooot for ur advice i got convinced i will apply the points u have mentioned ,,