In an ideal world, we wouldn't use TV to suppress our emotions. But it's not an ideal world, so let's do what we need to do to get through the day!
Binge-watching can be very helpful during a life crisis situation when you need to not feel your feelings and invest in a fake person's drama instead. This is all well and good (or actually, not good but we're doing it anyway) until you hit the last episode of the show, and your world away from your real life is suddenly no longer.
You have to leave the West Wing. Or Stars Hollow. Or Lockhart-Gardner, or Capeside, or Pawnee. And go back to your own surroundings, with the credit card debt that's piling up and the texts you didn't respond to because actually locking down a date for the drinks you're supposed to have with your casual friend from college seemed so overwhelming that you just closed your eyes and sat on your phone as though that would make the row of emojis she sent self-destruct.
Maybe your looming unaddressed problems haven't yet fully come back into consciousness. All you know for sure is when the episode cut to credits, your stomach drops like the one time you rode Superman after your friends peer-pressured you on a sixth-grade trip to Six Flags and you regretted it as soon as the coaster started its upward climb. (Trauma from middle school may or may not be a top thing we're repressing with television.)
This gut-dropping feeling will usually be very uncomfortable and precipitate a period of grieving for the show you just watched. Yes, you're missing the series itself: after upwards of 15 hours a week of a show over an extended period of time, the characters really do start to feel like your friends (or FRENEMIES Paris Geller I'm looking at you) and the communities really do feel like your home (still dreaming of living in Capeside -- the creek by Dawson's house truly is picturesque.)
But besides the actual show, you're probably also missing the safety of immersing yourself in a reality that's not your own -- which can make the withdrawal all the more painful. Fiction is powerful, you guys, and so is the human ability to repress!
Your emotional stages will probably look something like this:
1. Denial 
There's really no denying the fact that you've watched a series finale. But there are plenty of ways to deny that your time with the show is really over. If you've just spent months binge-watching a show that the rest of the world's already been caught up on, for example, you still have a lot of show-related media to consume ... right? "I can read all the recaps!" you might think. "Let me find those those think pieces I bookmarked when I was worried about spoilers."
Then you will do this. Anxious feelings will begin to creep closer to the surface. Then you will discover DVD extras ripped to YouTube. You will watch all of those. Then you will find fan videos recommended by YouTube. You will watch all of those. And as the last montage of Josh and Donna scenes set to a Coldplay song ends, you will worry for a second that you've really reached the end. Then you will read some fan-fic.
When your frantic googling of the show's title with various permutations of the word "scene" ("the good wife bar scene," "the good wife elevator scene," "the good wife car scene") finally brings up all previously clicked links, you'll start to feel dread approach the center of your chest. But before it really settles in, your body's defense mechanisms will turn it into...
2. Anger
With no new input from your TV show coming in, you're left at this point to consider all the ways the series ultimately wronged you. Why is that the way it went down with Luke/Lorelai, Will/Alicia, Pacey/Joey, Leslie/Ben or Jim/Pam? Why will I never be able to see what it looks like for Josh and Donna to be in a functioning relationship as adults who actually respect each other? I invested all that time and you're not even going to bring back Zosia Mamet's character for one single scene in the last season of "Mad Men"? I acknowledge it wouldn't have really made sense but she was an interesting companion for Peggy.
Eventually, your brain will realize this anger is all just because you're facing the reality of no new episodes. Then the fury will transition into disbelief at yourself.
3. Bargaining
Why did I watch so many episodes so fast? I could have made this show last for three more months. I legit skipped my friend's boyfriend's birthday party to watch six episodes two Saturday nights ago. If I hadn't done that, I would have gone to a birthday party that it was really kind of a faux pas for me to miss in the first place and I would also still have six more episodes to watch. Why did I regularly stay up two hours past my ideal bedtime because I had to know what was going to happen with Pacey and Joey even though I walked around tired for literally a month?
Why am I worthless.
4. Depression
Remember how TV was distracting you from your real-life problems? This is a cool stage where all of those come bubbling up to the surface and demanding you take actionable steps toward fixing them if you ever want to stop crying on the subway. You may stumble around with dead eyes for a couple weeks and make bargains with the snooze button each morning. You might lie there and wonder what's going on with Rory's journalist life, or if she ever gets back with Jess.
Eventually, you'll hit a point where you have to make some changes: find a new job, move to an apartment with cheaper rent, break up with the "not a boyfriend" sucking all the energy out of your soul. Hopefully this will give you a nice life reset, allowing you to move into new situations that are fine for a few months -- before throwing new crisis curveballs your way.
This is when the delayed depression wave will hit. You thought you'd finally moved forward, but now you need your comfort show more than over. Things are looking very, very bleak.
5. Acceptance
Then you'll find out "One Tree Hill" is on Netflix. You'll go to Season 1, Episode 1 and press play.