I really think its your soil and over watering (from worry/tending to the plants too much). Try to get something with way less nutrients and add them gradually in. Happy frog or something near that. First plants are a bitch, for a majority of people, and a great learning experience.
Even more important: stop programming yourself for doubt and failure. Doubt is a weapon to be used on your enemies, it causes death spirals. Its easy to be programmed into doubt, which is why most of society fails.
I know I come off as aggressive, but you need to have more faith in yourself and stop expecting shit results. Force yourself to be positive, call yourself out on your negative thoughts, and your mind will free up anxiety to see the route you need to take. You most likely have resources all around you to fix your issues your just caught up in a minor upset.
You made it this far and saw enough in yourself to invest in yourself, it must be meant to be. Learn from your mistakes, clear the mind, find new soil, and start over if you have to. If you can get soil fast enough, you can probable transplant the seedling into new soil.
Focus on getting photoperiod plants, autoflowers are a gamble. If you like seeds, start a mother from seed, clone from there. Its best to get all this out of the way at the start because it takes some time and you will most likely end up at that point after the autoflowers keep flopping anyway.
Best of luck to you.