182 - I'm Lost Without You Lyrics Meaning

This song might, as people wrote before, be about two lovers who cannot see each other all the time.
"I swear that I could go on forever again" -> They are having a good time, and they could just keep on living like that forever. "Please let me know that my one bad day will end" -> Being without the person you love can make a day bad, especially when you're having a hard time anyways. They just want clarification that they can see their loved one again, they wanna hear that the bad times will cease and that it'll become better eventually. "I will go down as your lover, your friend" -> no matter what happens, the speaker wants to keep feeling connected to their love - whatever happens, they are the LOVER, the FRIEND, making this even more pure: they don't even HAVE to be the lover, they are even okay with being their friend, if that keeps them connected. "Give me your lips and with one kiss, we'll begin" -> given the fact that this line leads to the chorus (the "begin", the hook of the song), this might be an introductory device, but also a request for "more" - they want to kiss, and then "begin", this meaning whatever one might imagine.
"Are you afraid of being alone? 'Cause I am. I'm lost without you." -> Pretty self-explanatory: They feel alone, fearful, anxious, (desperate,) and LOST without the lover.