Yesterday, I couldn't get on the internet, funny things happen. Now like there's no problem at all. What happen?

Maybe the problem was on the side of your ISP.

Impossible to answer this question because not enough information.  Remember that the Internet is world wide with billions of computers and hundreds of thousands of service providers.  At any moment in time there will be providers who are down, having issues, web sites not working, etc.  And yet the other 99% of people of the Internet are fine. Without knowing where you are located, who your provider is, what cable or fiber you are on, the exact time you have the issue, what it was doing, etc., there is no way to know if your area might have been affect by something.

But if it was not working for a brief time yesterday and came back without you doing anything, it was probably a local issue in your area that your provider had to fix.

You probably had a local temporary service outage. Without knowing where you are, it's impossible to pin it down.