You don't know what mood you are in. Like I can't figure out what I want to watch...I'm in a rut. Suggestions?

Hmmm it depends

Do you prefer more light hearted dramas or dark ones? Romance or action? Or everything mixed? Comedy maybe?

If you are not feeling like getting out of your comfort zone, then you can try the ones you never touched but are the types you usually watch. 

But if you're feeling adventurous, switch the type of dramas you usually watch. For example: if you like light, fluffy stories then  watch a heavy plotted, dark drama.

Obviously it's very difficult to figure out, so you can also try to pick a drama you never heard of. It can be a pleasant surprise.

I really like everything but historicals and full on action..... like some action is always welcome!  But other than that I'm pretty open. I guess I should have specified more. But I feel like I have a hard time finding a good dark drama 

When I'm feeling like that, I often take a break from dramas and watch a movie or two, and I generally look for humor and romance.  I re-watch Lee Min Ki in Romantic Island (and, running now, he's a delight in the series Because This Is My First Life) or Ji Sung in Whatcha Wearin' (it's a little bawdy but fun).  The Technicians is a wonderful crime drama,  and either of the Detective K movies ia a very funny historical (don't be put ff by that, this isn't like a standard historical)  crime dstories.  If you want a drama series,  Dalja's Spring and Come Back Mister  both cheer me up.  All of these are lighthearted, because when I don't know what I want, it usually means I'm feeling a little cranky or out-or-sorts.  Hope you enjoy one or two of these!