I Am Confused

How is being clingy and needy? This person and I used to message back and forth, he was the one who messaged first like everyday, but now just less and less. He has said he is busy, and he's back but not talks much as often, I miss the old him. Now I'm waiting for his reply again. Should I drop one more message? Should I talk with him about this? Would it be clingy and creeps him even far away? Or as everyone says just let it go? Ah my heart aches. :(