Is shouldn't drink beer in the morning - especially not after two valium. 
I prefer amphetamine and caffeine in the morning. Also in the afternoon and evening.
When do you sleep? And HOW?! 
I naturally tend to sleep a lot, and stimulants just help me to ward off my daytime sleepiness a bit and regulate my sleep better. I get 8 hours of sleep per night with stimulants, instead of the 10 to 12 I tend to take without them, but sometimes I still get really sleepy and have to nap during the day, and stimulants don't have much effect on me when I feel that way.
Do you know why you sleep so much? 
I could only guess about the underlying causes. In addition to the sleepiness, I seem to have a lower tolerance for sleep deprivation than most people; if I force myself to stay awake, I quickly develop brain-snow, which is caused by neurons firing randomly and raising the noise-floor in the brain, and eventually I start to hallucinate from it. Amphetamine somehow reduces the brain-snow effect when I'm tired, so my head stays clearer for longer.
This is fascinating, I've never heard of anything like it! I have heard of people hallucinating due to lack of sleep, but only after days of continuous wakefulness.
Have you ever asked a doctor about it? 
I asked my GP about getting a referral to a sleep clinic, but he said the local one would only be able to help if my sleep was being disturbed by a breathing problem like snoring or sleep apnoea, and I don't have any problems like that. I also asked about why I frequently get really intense postprandial fatigue, but he couldn't give any answers to that either. In my experience, Wikipedia is a far better source of information than most medical professionals.
In medicine and specifically endocrinology, postprandial dip is a term used to refer to mild hypoglycemia occurring after ingestion of a heavy meal.
The dip is thought to be caused by a drop in blood glucose resulting from the body's own normal insulin secretion, which in turn is a response to the glucose load represented by the meal.
Postprandial dip can produce irresistible drowsiness in some individuals, leading to a postprandial nap.
Intriguing new evidence points to a molecular and cellular basis for the previously poorly understood meal-induced drowsiness. Burdakov et al. (2006) have revealed that the rise in blood glucose that occurs after a large meal is sensed by glucose-inhibited neurones in the lateral hypothalamus,[1] a region of brain important for maintained wakefulness (remarkably, narcoleptic patients are found to lack 85-95% of these neurones[2]). These orexin expressing neurones are reportedly hyperpolarised by a glucose activated potassium current mediated by TASK family potassium channels. This glucose mediated inhibition is believed to reduce the output from orexin neurones to amineregic, cholinergic, and glutamatergic arousal pathways of the brain. This molecular pathway for the action of glucose on this critical orexin-expressing arousal centre in brain was previously entirely unknown.
While postprandial dip is usually physiological after a generous meal, a very sharp or sustained drop in blood glucose may be associated with a disorder of glucose metabolism.
The carbs in my meals come from low glycemic index foods, mostly steamed vegetables, and I don't get tired after eating high glycemic index stuff like fruit or glucose powder; only when I've eaten a balanced meal of carbohydrate, fat and protein, so I'm not convinced that my symptoms can be explained purely in terms of blood glucose levels, though an abnormality in my glucose-inhibited lateral hypothalamus neurons might explain some of my general drowsiness and excessive sleep problems.
There might be a issue involving the transport proteins that shuffle large molecules across my blood-brain barrier; transport proteins are a bottleneck for nutrient transport into the brain, and amino acids compete with glucose for binding sites on transport proteins, reducing glucose transport when the proteins are swamped by amino acids. There could be something about my physiology that makes me particularly susceptible to having my brain starved of glucose through that mechanism.
