You are doing nothing wrong. This is totally natural. Whatever you are spending time doing in real life will likely reflect itself in your ordinary dreams. If a considerable amount of thinking time or study time on any topic, be it LDing to horseback riding, you should be having dreams about it. Some people think you should RC every time you think about lucidity, (I really don't believe that, but it may be worth a try since it's apparently successful for some people.) Just keep using the techniques, and if your unconcious self already has lucdity on the mind, you should be LDing in no time.