How can you tell if your falling in love with someone?

I guess if whenever you see him/her, you start to feel happy and your hearts starts to pound in your chest. When they smile at you, you smile back the biggest cheeseiest grin possible. You talk about him/her to your friends non stop and dream about him/her every night. I guess that's what it is. I mean as long as you feel it, if you have a gut feeling that you might like him/her more than a friends than maybe your in love. Hope this helps. :)