That can be in great part due to SI, Survival Instinct, our brains are wired to enter that survival adrenaline mode when they recognize we are face to face with death, which is a smart move by nature, but it makes most suicide attempts a lot more unpleasant. Very. Some people experience it easier, some worse. And that fear of regret is not unfounded, it is a thing that can happen. Lot of jumping survivors mention it. Brain can do that and a lot of attempts end that way. Which is a shame in terms of the added suffering to those people who have already reached that low point, regardless of their final outcome.
But I don't think that alone should speak for whether you "really want it" or not.
Nor that if recognizing it's just a natural instinctive response, and that's all it is, that means you really should do it.
I don't think it should go either way.
We are not in your head so we can't tell what you "really want", and sometimes we feel like we are not even in our own heads to tell that. Sometimes we can't. It's hard to use the brain against itself, to excrutinize past instincts and fears and confusion and wills and end up at a stable position. If you got a battle raging at the moment between those opposites, of life and death, regrets and release, I'd say it is very worth it to examine it thorougly. Like I said, past the instincts and past the pain, whenever that's posible which will not be all the time. If you can find a source for your fear of regret beyond the natural, or reasons for why you want so desperately to leave aside from the general pain, deeper ones, that'd be a win, and clear a bit of the path forward.
Don't know you and don't know what would be the best way to do that, how to ease that confusion even if just a little which I'm sure would be appreciated, but I can only wish you the best of luck with that, and that you can get easier days soon. hugs <3