If my heart stopped beating, would I have enough energy to walk out into the other room 20 ft away before I passed out and died?

Only when I sat on my bed, my blood pressure and counsciousness slowly went back to normal.

Not sure if this is going to be a good answer to your question but I can share some bad experience I had in September this year, since it may in some part describe the way you could feel when something like this happened to you.

Really bad things started to occur at night when I was preparing myself to go to bed. Last thing I was able to do with no issues was washing my teeth and right after that I started feeling that my blood pressure decreased rapidly. After a couple of minutes it came to a point that I couldn’t think anymore and I wasn’t even able to recognize myself in the mirror. I was just standing, holding on to the sing, looking at the mirror, and I was like Who the f-word is that?

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It was like my consciousness was about to switch off completely in a matter of seconds. The only things I had in control were my limbs so I kept holding on to the sink and did my best not to fall to the floor. Since I also had some control over my legs, I tried to make some steps and VERY slowly I managed to get from the bathroom to my bedroom. Now I realize it was pretty dangerous since it involved walking up the stairs to the upper floor, however, I always had something to hold up to.

One day in September I suddenly started having symptoms similar to cold or flu. That day was very hot so I thought my symptoms were partially caused by high temperature outside. I drank some water and waited until late afternoon till it became a little colder. Then I went outside to do some shopping and my other everyday businesses.