I had a rotten day too. I bought fusible batting for this bag I am making. WHY I did what I did...I have no clue. I read the pattern directons wrong and ended up ruining an 18" X 32" piece of fabric AND the batting. I forgot to put the bag top on top of the batting. I ironed right on top of the batting. LOL So I cut another piece of batting...luckily I had just enough of it. And then I gave up for the day and tomorrow I will cut another piece of fabric. The one I screwed up is the underlining and then I need a piece the same size for the lining. Glad I bought extra yardage of that fabric.
Clearly mine was not quite as bad as your problem but I've been trying so hard to make this bag perfect and of course I screw it up.