This song means that almost half your heart is let go. The other half walked away, and you have so much to say but they're just gone before you know it. It's when you love somebody that loved you back, but now it's time for goodbye and you're in denial and don't think its true. And having to regret the feeling everytime you wake up "Gettin up, gettin dressed, livin with this regret, but I know if I could do it over".
And you find out that the feeling is so hurting that you feel like you want to go back in time and start over. But, it's already done. Then in the end, you find out there's more to hope for. You might be able to try to tell that person you love him/ her.