Modafinil

I tried to fake narcolepsy to get it. Had to do a sleep study....my plan obviously failed. Some doctors will prescribe it off-label for shift work sleep disorder. I'm sure you can convince one doctor that you'd qualify based on IB hours.
I honestly can't stand adderall because it makes me paranoid and anxious. Gonna try to get the Modafinil prescription via the above advice.  

Absolute gamechanger.

Go to the doctor and tell them you're having difficulty staying awake, and your job demands it. You'll find a doctor that will prescribe it. You can also tell them you believe you have sleep apnea, tell them your girlfriend heard you snoring a lot, and get tested for sleep apnea. If you have it (even if it's mild), then you can get Modafinil. A lot of people have it that don't think they do. I wouldn't mess with shady overseas pharmacies. I'm sure there are decent ones, but I'm not that risk-tolerant. You can also take Adrafinil. You can purchase it in the United States without a prescription. Adrafinil is a prodrug, and your liver processes it to have the same effects as Modafinil; however, it's not as potent. It can also be harmful to your liver over time. Some people take Milk Thistle with it to help their liver. I took Adrafinil a few times, but to be honest, it wasn't worth it. Go find a doctor that will prescribe it. It won't be as hard to get a prescription as you think, especially if you can make the sleep apnea or shift work argument.

Modafinil works, but it isn't a Limitless pill. It doesn't make you more intelligent, and it just doesn't let you go to sleep. It also makes some people run to the bathroom, and it makes their pee smell. You will be tired while on Modafinil after working all day and night, but your body won't shut down. You will be mentally exhausted, and you will have trouble thinking. I only take it on days that are going to be extra demanding. It also has diminishing returns the longer you take it.