"take me back to the days of last summer"
i think this is referring to the past relationship they had together.
"you're falling hard and your taking me under"
i think this means that she is beginning to fall for someone (or him?) while he is realizing that he is falling for her.
"and maybe i'll get lucky, she'll come flyin back to me"
again, i think this is referrring to a past relationship, where he just wants them to be together again.
"i'm gonna make it up to you"
he realized what he has done to screw up that love they once had and wants to fix it.
"take me back to the days of last summer" i think this is referring to the past relationship they had together.
"you're falling hard and your taking me under" i think this means that she is beginning to fall for someone (or him?) while he is realizing that he is falling for her.
"and maybe i'll get lucky, she'll come flyin back to me" again, i think this is referrring to a past relationship, where he just wants them to be together again.
"i'm gonna make it up to you" he realized what he has done to screw up that love they once had and wants to fix it.