"Repent" simply means to turn around and go the other direction, in this case, to turn away from sin and turn towards God. 

You are deciding to make a change.  You're going to have to trust God to show you how to make it work.  He'll give you the strength to keep walking in the right direction.  Right now you're turning around and walking toward God.  We can only live in this moment.  Don't worry about tomorrow.