As so many have already said, no you are not alone!
I have been doing fmq for many years both on my dsm and now on a sitdown longarm - and quite honestly there are many things that can contribute to a “no good, awful, very bad day” . As many years as i have been doing it i can still make a mess of things. Sometimes i am too tired, or rushed, or tense or not feeling very confident at all when i start. Sooner or later it works out, although sometimes later than sooner. But its ok!
Maybe try practicing on some small items first - and once they look like you think they should, then jump into something a little bigger. Try not to get discouraged and please try not to let too much time go by before you try again. For me waiting too long to “get back on the horse” is not a good plan.
I would imagine that everyone here feels your pain... do you have a quilting buddy who can be your “cheerleader” to get you over the hump? I am fortunate enough to have mine living right next door and it’s amazing what a few kind words and a rah-rah-rah can do when your confidence is nowhere to be found.
Please dont give up - those beautiful quilt tops need you!