Hey kword,
i had lots of experience with dexedrine, which is about the same as adderall except it's a better buzz (less edge, more calm), and it's slightly easier on your heart.
I used to take dexedrine 20mg a day for up to two weeks, with only about two hours of sleep every night, and then quit and wait a month. Unlike you I didn't use it to study, I used it to help me write.. But mostly because the buzz/high I got was incredible. And I couldn't quit.
So I became an addict.
In short I did get all your symptoms.. But only when I was deep into the addiction (6 months of going on runs!!) obviously it's very bad for your heart, and whether or not you're prescribed it, the stuff is still speed (amphetamines.) speed is addictive, because it makes you feel you can do anything, and enhances your cognitive abilites in many ways.
I even had times when I was so addicted to the stuff (couldn't give up the buzz for my life!!), where my heart would hurt, beat really fast, and I would have trouble breathing!
The fact that i'm still alive (there were many times where this stuff could have killed me) proves that whatever damage you did to your heart is probably not extensive. Because I went through your symptoms about 30 times or more. I was unwilling to quit, and that's what happens.
I think you experienced "overdose" symptoms, however, not because of abuse or addiction (mine were caused by addiction/abuse.)
you just foolishly doubled your dosage.. Speed is not a drug you can do that with. The only way to use speed for any reason (to get a buzz, to do work, to stay up for days on end) is to use the lowest effective dose. If you lose some of the good effects after using the same dose for a long time, you can try adding an extra 5-10mg here and there. And see how that works. If it works well, you might have a body that can handle it--johnny cash used to take 20 dexedrine pills a day, and 20 sleeping pills every night. It's a matter of tolerance--and only if you have a strong cardio/heart. I don't have a strong heart, that's why dexedrine ruined my health.
Give your heart time to "repair" after this "episode", and if you use adderall during this period, keep it low. I would say no more than 20mg a day. That's really all you need, anyway.
40mg of adderall (if crushed up, and taken all at once) is equal to at least one good hit of crystal meth. And doctors prescribe this stuff!
Speed is dangerous.. But not if you're careful and if you can quit before it ruins your health. My health is ruined permanently because of foolishness and self-loathing. Don't make my mistake.
Hope this helps!