J.V.
I so hear you. My little guy was sleeping great till the 4 month sleep regression, and now we are on the 6 month sleep regression. I am a total zombie and super grumpy mommy to my 2 year old!
My plan is to just keep hanging on, and hope that he sleeps again soon. I know it's all about habits, so I doubt that will happen. What I do know is that putting them to bed later just makes it worse. Try 15 minutes earlier every night.
Also, just hang in there. You are in wonder week hell zone --from roughly 15 weeks to 26 weeks there is just so much going on! My guy has been wide awake from 10-12 every night, and then is wide awake at 5!
They will settle down again soon.