I underwent a similar thing a few months ago and mentioned it here aswell.
My problem was that I was playing the usual easy G,D,C songs that all of us start on, I just got bored of the material I was playing although I never got bored of actually playing.
I sort of underwent a transition from playing the "usual" beginner songs and started listening to the radio and and dug out some of my old LP's. All the enthusiasm just came back immediately as I started playing songs I actually liked and also chart songs that my kids liked. Nothing gets me motivated more that playing Lady GaGa - Pokerface and seeing my 6 year old daughter rush into the room and start dancing and singing! Don't forget some of best dance/pop/techno songs wre written on a guitar and sound fantastic stripped down.
I don't know if your playing barre chords but these are the key to progressing, chords like Bm, F, Fm, Gm are a pain to learn but well worth the effort.
Keep aty it and mix it up.
Ry
Epiphone EJ200 - Epiphone SG400 - Fender Strat Blacktop.
Blackstar HT 40 Club - Vox VT30 - Behringer ACX ultracoustic 1000