Caffeine over-stimulation?

so don't usually have a lot of caffeine. there was one time that i was on thermogenics for about 3 weeks, but I realized that i should stop taking them. but recently, I've been working at a construction site for about 7 hours a day and then going to the gym, running 5 miles, and doing weights. this has been making me pretty tired, so I've been drinking lots of coke zero and an occasional 5 hour energy. its been a week since this started and today especially, i seemed especially tired. i don't think it was sleep deprivation because I've been getting a good 10 hours a night. i'm going to stop all caffeine consumption for a week and see how i feel. i know to expect symptoms such as headache and grumpyness, but my question was what the different symptoms were between caffeine addiction and caffeine overstimulation? thanks