I am not too sure about your blood pressure and your increased joint pain. I have not had a similar reaction (though on adderal XR).
The rebound effect is the process by which the chemicals are gone in your system but you still have lingering effects. For a normal person who takes a stimulant they get high (agitated & speedy), therefore their rebound is depression. The rebound is not as intense as the high, but can last longer. The more they take, the harder and longer the crash. For a person with ADD, the opposite happens (well opposite but in a normal state, not depressed). We get relaxed after taking our medicine but in turn after the chemical has passed through our system we are left with the rebound effect in a agitated hyper state. Well, that's all the time I have right now I have got to get going to work! I hope this helped you out a little