This EXACT thing happended to me! like...EXACTLY! this is so weird! I was working on tucks, and when i did my bhs, i freaked out in mid air and landed on my neck, and didn't do that, a standing bhs, or bwo (well, i only lost my bwo for about a month) for almost a year! But what really helped me was to do them with a HUGE spot off the end of the tumble trak. Like, my coach calles it the superman spot, lol. she literally had to pick me up and do the skill for me the first few times so i would be comfortable with going backwards again. Then after doing that for a week or maybe less, i got my mom to help me with them at home on the trampoline, then on the grass, and then it seemed to have just clicked, and i would do a standing bhs!
Just make sure that you don't get to frusturated w/ your self. I know exactly how you feel, i cryed myself to sleep for months. Just don't give up. what i always say to myself is to just do it once, your body still knows what to do, you just have to do it. This happened to me about a year and a half ago, and now i am doing layouts and fulls! If you have any other ?s, please private message me

good luck, and don't give up! If it was the tuck that scared you, try not to think about those for awhile, that will just make it harder.