Help me reset Terminal after sudo command mistake

Help me reset Terminal after sudo command mistake

I recently installed a cracked version of a program and it instructed me
to block outgoing connections by following these instructions below
Step 1 Click the "Go" menu, select "Utilities," and then double-click
"Terminal" to launch the utility.
Step 2 Type "sudo cp /private/etc/hosts ~/Documents/hosts-backup" (omit
the quotes here and throughout) to create a backup of the "hosts" file
before editing. You can open this file later if you find the changes you
made to your system resulted in unintended behaviors.
Step 3 Type "sudo nano /private/etc/hosts" in the Terminal window, and
then press the "Enter" key. "Sudo" indicates that you want to gain
administrator access, "nano" tells Terminal the program to use -- in this
case, the Nano text editor -- and the pathname indicates the location of
the "hosts" file.
Step 4 Type your administrator account password, and then press the
"Enter" key. You must set up a password for your account to make changes
in Terminal. If your account doesn't have a password, select "System
Preferences" in the Dock, click "Users & Groups," select your
administrator account, click the "Change Password..." button, and then
enter a new password.
Step 5 Press the down arrow key to position the cursor below the default
set of rules. Don't edit any of the existing rules as they set your
current firewall settings and allow your computer to function properly.
Step 6 Type the domain IP address of the website you want to block
communication with in a blank line followed by a space and the domain
name. Use the format "0.0.0.0 domainname.com" and put each entry on a
separate line.
Step 7 Close the window, enter the Terminal application again, and then
type "dscacheutil -flushcache" to reset the cache and apply the new rules.
I only made it to step 3. I was asked to insert my password and since then
my computer has been slower and the color wheel will not stop spinning
when i open certain programs. I'm even having trouble force quitting
programs and youtube videos refuse to load.
Is there any way that the Terminal can be reset or this problem can be
rectified? Your help is greatly appreciated.