what do we call that feeling?

have you ever feel something that u don't know how to explain when you hug or kiss someone but its somehow make u feel like crying. it make u sad and happy in the same time. i felt that a few times with a few people. maybe its the feeling of don't want to let the person go or the feeling of grateful that the person is in your arms now. whatever it is, i don't know. what i know is the tears is going down my face slowly.

"this is complicated"