Sounds familiar. Happened lots of time on two of my Win 8 computers.
There was frequently some wackadoodle mischief going on.
Yes, the updates could have caused it. I went through some rough patches and bumps. It got pretty bad. I had my pro Guru fix things and I ran some Spybot Search & Destroy. Now everything runs like a fine Swiss watch.
You have several options for sleep. Extend the time. Tell it it never go to sleep. Dispense with log on entirely if practical at your place. Set it to log on automatically.
Since there are no other users here I just set it for automatically log on. *( But on it's own it reset and asked for the password ). So I just got tired of fooling with it and now when it reboots it asks for my password. I just go ahead and type it in.
There are other options: You can use a 4 digit pin to log on too. Or a picture.
But let me say that after I boned up on all of the current cyber mischief, hackers, cruisers, bandidos, data miners and so on, it became apparent that the problem is growing. Some of these have software set to cruise constantly trying to break your code, hack you E-mail, steal ID's and personal information.
The Win 8 defender and firewall are deemed not sufficient protection.
All things considered I just tolerate typing in the password when required. It is recommended at 8 combo of letters, upper case, lower case, and symbols. These combinations of such a password are said to required possibly decades of effort to run trough all, trying to use brute force. However, there are also "people" who sell passwords and E-mail user names.
And if you are wireless some Guy cruising the streets near you can access your computer too.