yeah cause cortisol fluctuate very fast in the body. So fast, that you can feel like shit stressed in the morning, and at night be totally relaxed and horny. Normally, cortisol levels are high when you wake up in the morning and they decrease during the day. But if you have something or some things buggin your mind, they will stay high, or higher than normal, and will kill your libido and can cause trouble falling asleep.