I've had this happen a few times, but the most severe were with Gaksital and Bu Bu Jing Xin. After these two...it felt like I couldn't leave the world they brought me into, nor did I want to. It actually almost hurt to think about leaving them behind, that's how much the characters meant to me and their story. I re-watched them multiple times, but it just ended up being harder because I knew what was going to happen, so I soaked in more and more of the minute details I missed the first time watching them. Gakstial was a little worse, because even falling back on my true favorites didn't help at all, and I ended up finding faults in them I didn't previously because they didn't match up in my heart. >.<; The only thing I could do was stop watching dramas for a little while and switch to reading something completely unrelated until I was able to start a new drama. I've never forgotten the feelings and stories of those dramas though, their engraved in heart for good.