The drops of blood when the nurse/doctor removes the needles is common. If the needle happens to go through a capillary or something it will sometimes bleed a little and will also leave a bruise. It probaly won't happen next time and it doesn't diminish the effectiveness of the treatment.
As for the heart pounding, it had been an issue even before you went, right? A lot of people have a nervous system that is wired to naturally be sympathetic dominant. It makes your body over react to things. The heart pounding is probably a symptom of an imbalance in your nervous system. But, just have faith and keep going, the doctor can't change things a lot in 1 treatment. Your symptoms may temporarily feel worse, especially after the first visit, but they sould get better and better as time goes on.