I've lost my groove

Running has lost it's thrill & excitement for me. What a bummer. All that mojo I had a couple of weeks ago has gone away someplace and I can't seem to find it. I don't wake up excited to tackle my run anymore and that freaks me the f* out! I didn't even go 2 miles today without stopping twice and decided that I didn't even want to finish the damn run and walked home......yes, WALKED. My neck was killing me and that's all I could focus on. My mental motivation is at an all time low, my physical ability to run is at an all time low, my spirit to do this is at it's lowest yet...and I can't even take a break because then it's even worse when I start up again! Yikes! I'm lost. I was up to running over 4 miles, which is GREAT for me, but I'm back at square one. Like I'm brand new to this and I'm really mad, pissed, frustrated, confused & perplexed about it. I really don't know what to do.