I agree -- don't trash it. I also agree that it would help going forward if you can figure out what went wrong, but maybe setting it aside and doing something else before going back to it will work better.
I have had this problem (most of us have). I have added sashing between the blocks, I have remeasured and adjusted the seams of the smaller blocks. I frequently make the blocks larger so I can trim them to size (especially HSTs), but I also make more blocks than I need so I can use the best ones. Sometimes a good night sleep helps me see things better, but sometimes I just put the project aside and go back to it later. I find that the more I piece the better I do, but if I have a lot of time between sewing sessions it is like I have to start all over.
Good luck with whatever you choose to do -- but don't let one problem kill the pleasure of making a quilt.