I was diagnosed with ADD as a child, and they put me on Adderall. Like you, I was only taking one pill a day, but unlike you I only took a 5mg pill. It screwed me up, for life. Though no doctor or study will admit it, Adderall has some dangerous and life altering effects that will haunt you for the rest of your life.
Here's a simple story. Every morning I would wake up, get out of bed, walk downstairs, eat a bowl of cereal, and take a pill. I would go out to the bus stop, dragging my feet with fatigue, and hopefully not miss the bus. Two hours later I'd have a panic attack. Same time, every day. The rest of the school day I was happy. I paid attention in class. I hung out with my friends. The bell would ring, I'd catch the buss home. I'd walk into the house, crawl up the stairs, and crash. Most of the time I only slept till dinner. Sometimes I slept straight through till morning. This means I only had a total of about 8-10 hours a day I was actually functional. I never did any homework once I got home. When I started working, I suddenly had a huge new problem, panic attacks at work. Throwing up from over working myself. Loss of weight and appetite.
I quit Adderall cold turkey after taking it for two years. To this day I still have panic attacks and I still crave it. I never had severe insomnia before I started taking it, or panic attacks. I was mildly depressed, but I never had suicidal thoughts until after the Adderall. I got off lucky, Adderall can cause severe psychotic reactions in some users, such as paranoia and hallucinations.
The Adderall made me feel good, and it helped me concentrate in class, but the health risks just aren't worth it. If you need to pull an all nighter, put on a pot of coffee and plow through it. It doesn't keep you up as well, but it's safer on your body by a long shot. See a doctor about getting off it, stopping cold turkey like I did can be bad for your health as well. If you don't feel safe seeing a doctor or councilor, try to taper off your use, but either way, get off the stuff. It'll ruin your life.