The solution to every problem is NOT to "Take a pill."

Diagnosing vitamin deficiency in a Medium article based on one symptom is questionable at best.

You say you are too busy to cook. Maybe it is stress. Maybe you drink too much coffee. How your body reacts to caffeine changes during your life. Could be what you eat or when you eat is the problem.

Have you tried meditation? You can buy one-time guided meditations that costs about $4 and then you can listen to them as often as you want forever. Meditation can address more than just sleeplessness, is cheap and does not introduce external pharmaceuticals into your body.