It is normal, because you are not in love. You are in infatuation and lust. Love doesn't just fade when you get bored. There is nothing wrong with getting to know people and finding that they do not meet the requirements you need in a partner. Assess what your standards are and important qualities you look for in a partner. Don't date people who do not fit the criteria, that way the relationship you do form will have more substance and you will find yourself "falling out of love" a lot less often. Keep and open mind, and open heart and don't look to hard. Often, real love, comes from the most unexpected places. Enjoy the journey. Good luck :)
Personally I don't think that falling out of love is something that happens quickly or easily. You should take a few days and really look at yourself and ask, is it really love you're feeling? Sometimes being deeply infatuated with a person can feel like love, when in reality, it isn't, and we've only fooled ourselves.