Why cant I stop thinking abut her? ]:?

Alright so im 20 years old, and every thursdays me and my family go to this restaurant to see a car show. There is a hostess their that I always thought was so beautiful. She seems so humble and joyful all the time and always took good care of us. Im pretty sure that she is single too. Anways, I was never able to talk to her because of how busy she looked. Last thursday was the last car show so finally I got the guts to give her a Little note stating that I think she is very pretty and maybe we can be friends and hang sometime with my number at the bottom. She smiled and told me thank you. Every thing seemed so great. for the next 3 days, I looked at my phone like every 10 minutes to see if she called or texted me... and she never did. SInce then, ive felt so sad. I always think of her cute smiles and end up sighing. This is so strange to me because I dont even really know the girl and im acting like I just broke up with her after a 10 year relationship. I just moved here to San Diego from Hawaii and seen a lot f good looking girls, but she is the first girl that caught my eye since I got here... My friends just keep telling me to get other girls..but its like I dont want them. sigh idk I just wanted to share it with some people and ask what they think about this.