how do u know if ur in love

what is love and why do we have it are the two questions i ask the most and im not sure if love is natural or not but the true question is how do u if u are in love or not. thats only one main thing i wounder( prob failed that word). i just need answers so if u know the answer then plz comment and if u don`t like any of the spelling comment. i will also be glad to see other questions u might think of that i didn`t. (this thing is pathetic 100 words for a journal really)