The way I knew I was in love was my hands would sweat with just the thought of him. Being around him seemed to make the sun shine. He made me feel like a million dollars and no one had ever made me feel that way. I was never happier than when I was with him. He made me laugh, feel good about my self, and also made my heart race.
You can't stop thinking about them; you want them to have whatever they want and are willing to give up what you want so that they can have what they want; you feel like you can't live without them; you basically stop being your usual self centered and self serving self and start being a giver instead of always thinking about what you can get and what's in it for you. Of course, this only lasts for so long, then you'll turn back into your old self ((as will they))!!
You get this feeling when you see that person or are around that person. You also smile a lot when you "sense" they are near. (you can't help it). Whenever you talk or try to talk to them,, you kinda lose words and get nervous and try to be extra careful that you don't say something stupid. Don't worry, you'll know when your in love. hope this helped :)