I think that the entire song, A Little Bit Longer, by the Jonas brothers is about love.
For example in the first four lines of the song it says,"got the news today, doctor said I have to stay, a little bit longer, and i'll be fine". I think the news is that his girlfriend broke up with him and that the doctor mentioned may be a love doctor that said he will be okay in time. The next few lines are ,"when i thought i'd all been done, when I thought it'd all been said, a little bit longer, and i'll be fine". I think that means the fighting and lies between him and his now ex-girlfriend is now finished and even though it hurts now it won't hurt forever. In the next few lines it says," but you don't know what you got till its gone", indicating that the boy thinks that the girl doesn't know what she is giving up. "And you don't know what its like to feel so low, everytime you smile or laugh you glow, you don't even know", maybe he means that he feels so sad and when he sees her smile or laugh it hurts because he still loves her and she doesn't know how much pain she has caused him. I think that the lines "all this time goes by, still no reason why" means that he doesn't understand why they aren't together even after all this time has passed, he is confused. Also the lines "waitin' on a cure but none of them are sure" refers back to the doctor love doctor reference.