This one I can help with (maybe).
I went through about 2 weeks of this and I figured it out. I was moving too much during the swing with my lower body. ('sway' if you like).
Sometimes this causes you to stay too far behind the ball (mild reverse pivot). You cannot complete your swing properly, it gets abbreviated and you finish your follow through too early.
My cure was easy once I knew what it was (but it took a good weeks worth of experimenting). Basically I kept weight distribution a bit more even, and I made sure to swing to right field, completing the path of the club head _through_ the ball.
My 'drill' that helped when I was home was to take a kitchen chair, and put it about 4-5" away from my right hip and swing wedges which IMO should have no sway. Go up to a mid iron and make sure your right hip isn't hitting that chair. (for right handed golfers).
I can't say this is your problem, but I wanted to post this because I had the exact same problem for a spell this summer and this solved it 100%.