I read up how to start having lucid dreams, but the only problem is, what if I accidentally think I'm dreaming but it's real life? Its really unlikely but I've been sort of paranoid ever since I saw that lucid dream episode of American dad lol. Also, when do they end?
Pinch yourself, if you are hurt by the pinch you are not dreaming.
Look at yourself in the mirror, look away, remember that image, and look back. If the image is different, you are dreaming.
If you keep giving yourself these little reminders then subconsciously your brain will ask those questions and you will remember if you are dreaming or not. It takes a long while though, to "master" the art of lucid dreaming.