It's not cowardness, it's survival instinct. That said, your SI was probably right because your odds of succeeding from the 7th floor were not that good.
-- There was a russian guy who recently survived falling from the 19th floor onto a car. The guy litteraly got up and casually walked, he got away with a concussion and spinal compression. (There's a video somewhere).
The guy survived probably because modern cars crumple on impact and it dispersed an important amount of energy that would otherwise have liquefied him; he most likely landed on a part designed to have a tolerance to flex inward toward the interior of the car.
Things like this are just a friendly reminder that "luck" can ruin our plans very effectively.
(In the russian guy case, chances are he was thrown out of the window and didn't try to jump, but my point still stands.) --
Anyway, don't beat yourself up, being incapable to do it for some time is absolutely normal. It's easy to make the decision but very hard to take action. We are pretty much all wired the same way because SI is "engineered" to make us avoid life threatening situations at all cost and we have it laser engraved deep in our cells/dna.
I believe that fighting SI requires more thinking than it requires courage. It takes a lot of time for your brain to sort through the pros and cons and i believe that people who choose (or can't choose anything but) a very violent method for example, are courageous yes but above all convinced.
Maybe you're just not ready yet, maybe it's not your time, maybe you haven't given enough thought, maybe something or someone inconsciously makes you stay, but you definitely need to not rush things and accept that changing your mind is not a weakness.