Don't know what to do with this

[Craw]

I am making a hat for my son. It's this pattern. I made this pattern once before and knitted it flat and it came out great. This time I changed it to circulars so I wouldn't have to seam it. Every where I decreased, even though I pulled the stitches quite tight, I'm getting a gap that gets wider and wider as I go along. Hopefully you can see from the pic. It's still on the circulars and about to go to DPNs ... but ... what should I do? Frog back to before the decreases? Go to the DPNs and finish and try to sew up the gaps? What did I do wrong?