Alone or Together?

It took a long time for me to be able to open up to people. I used to be shy and scared and never show any kind of emotion whatsoever. Through different experiences and relationships, however, I have become more open, more willing to show what im feeling.

But what happens when you want to turn that off. What happens when you want to shut down, to numb yourself, to make yourself not care anymore, to go back to being that person who doesn't want to share anything. How do you do that?

And which way is better?

Doing it alone, not letting someone in, working out your struggles by yourself, but knowing that because you don't you will miss out on maybe something great?

OR

Letting someone in, not doing it alone, but also taking the risk of rejection, hurt, stress, pain..?

What do you do? Do you trust everyone? Do you pick and choose who you let in, how do you know?Because you can't be open sometimes and closed other times, it's who you are, you either want to show emotion and you let people in, or you don't, you numb yourself, tell yourself you can do it alone. Which way is better? Which consequences are worse?