Jetpack disappears after 2.4.2 upgrade

I am not a pro. I am just a guy with a website and every now and then I try to improve things. I use Bluehost.com webhosting for my website and I regularly get notifications about upgrades for the themes, widgets and so on and I implement them with one click. Things usually are pretty smooth.

Yesterday, after upgrading my Jetpack to 2.4.2, I was was putting my Twitter widget into the Showcase sidebar, just to see how it affected the look, and Jetpack just disappeared, along with my Facebook,Soundcloud, Photo Carousel and Twitter widgets.

There is no sign of Jetpack. How do I get it back?

https://www.ads-software.com/plugins/jetpack/