Unless your coach is a doctor, it doesn't sound like he should be prescribing anything because you have low blood pressure, or low energy.
One important thing I haven't seen yet mentioned is that, although the beneficial effects of athletes taking caffeine are well known, apparently drinking coffee simply doesn't provide these known benefits of caffeine. It's probably better to drink Coke or Pepsi (caffeine plus sugar).
However, to say that drinking coffee is unethical is, in my opinion, blowing things way out of proportion, and equating coffee to EPO makes a mockery of what should be considered a serious issue. What separates coffee from other banned drugs, or blood transfusions:
1) First and foremost, coffee doesn't actually bring the known performance enhancing benefits of caffeine. Something else in coffee seems to interfere or cancel the effect of caffeine. Any improvements are simply a placebo effect.
2) There is no mystery behind caffeine "the drug". It is not some "manufactured" substance created in secret labs, made available through underground channels, for enormous sums of black money. Zealous officials highly motivated to prevent performance enhanced competition know about caffeine, and in small amounts, they are simply apathetic. The performance enhancing benefits are simply too small to warrant concern, or merit such a personal intrusion on the lives of athletes.
3) Coffee is a part of many peoples' everyday lives. In the small amounts permitted, coffee is widely available to all athletes, and is not dangerous and life threatening.
So through a thoughtful combination of universal availability, low price, lack of risk, and small performance benefits, drinking a cup of coffee before races simply doesn't rank high enough to become a moral or ethical issue, without devaluing the concept of ethics and morality.