I hate to be "that guy", but the reality of the situation is that Amphetamines as a class have a pretty wide therapeutic index. You could take several times that dosage and you would most likely experience overstimulation, panic, palpitations and/or anxiety. Ultimately, even though it can be an intense experience, Amphetamines have a wide range of relative "safety" when compared to say, Opioids, in which a lethal dosage is significantly closer to what is required for analgesia/euphoria.
Do with this knowledge what you will, but we are not a D.A.R.E. program. It's difficult to lethally overdose on Amphetamines and I'm saying this because I want to put your mind at ease, not because I want to encourage a depraved stimulant binge. I had an experience with Adderall when I was a teenager in which I took 180mg. I thought I was going to die and was in a state of utter panic. The panic only came from not knowing anything about what I was into. I'm not proud to say it, but in the future, I would routinely approach this dosage when going through binge patterns.
You're not going to die, but that doesn't mean that this is socially or physically healthy behavior. It's the secondary effects of Amphetamines that will cause the most initial damage in your life, not the drug itself per se. Lack of sleep, hydration, nutrition etc.