The day after...
It's frightening to be completely consumed by someone, they are literally all that's on your mind 24/7 and there is nothing you can do to change it. Every part of you wants for them, and when they are gone all you do is long, and try to fall asleep to how you remember them feeling next to you, and in a silence you drown. The next day you wake, and all seems better and lighter in heart, because you know you'll at least see them, though all else would be welcome. Let's face it, given the chance to fall into everything they are, you would take it. Not half hardheartedly, but so much in fact that it terrifies you. You become the underlying weakness given to them, and they become your strength, as much as it seems the opposite. Not everyone is lucky enough to find someone who will not only pull them from the depth they had previously been in, but also hold them up, and stand by them in future troubles.