how does jekyll feel after taking the drug?

The drink caused him pain and nausea, but as these feelings passed, Jekyll began to examine the results of his work. In fact, he felt strong, sensual and wild and he noticed that his body had changed. His hands were smaller and gnarled looking, and his clothes were suddenly far too large, which led him to conclude that his alter ego, which he later named Edward Hyde, was a small, dwarfish man. Jekyll reasoned that this identity was physically smaller because it represented his evil side which had previously been repressed and carefully controlled.