It's quite normal to have people not believing in you or your idea. Jeff Bezos wasn't able to pitch the online book store, google was turned down by yahoo and for me more tangible, my professor Goetz Werner, was turned down by his former boss and consequently started his dm drugstore chain. It's now a multibillion dollar business for him. He has since then passed on daily operations and is now teaching entrepreneurship at our uni (Universitaet Karlsruhe, Germany).

Just like ideas, people evolve. The trick is to not feel too depressed about rejection. Practising helps :)