I want to restart playing guitar, but don't know how... Any tips?

I played electro guitar for about 3 years... I stopped playing a year ago due to a bust schedule... Now I want to restart playing but every time I get it to my hand I am very frustrated that I cant play as good I was, and although I know I need to start practicing simple stuff, and then advance like before, I get really bored because of being repeating myself. How can I tackle this problem? Also I would love suggestions of songs in different levels, which I could play as I start advancing again, I don't want to replay the old songs I knew...