Here's what I would do, for what it's worth. I would let the filter run for a couple hours, then vacuum again. It sounds like you got a ton of nasty out already this morning, so I would vacuum just to filter, not waste and see how far you get before you lose suction. If it seems to be working well that way, keep vacuuming to the filter. Then after you're done vacuuming, give it a good brush down and let it settle again.
I'm not sure how your return jet is pointing, mine is pointing slightly downward and makes the water flow slightly counter-clockwise. This keeps the 1/3 to 1/4 of the pool bottom pretty clean and the "gunk" tends to collect in the center of the pool and to the left half of the return jet (my kids call it the whirlpool effect). Maybe you will have a pile of gunk in the middle too. Try vacuuming there and see what you get.
Remember to adjust your chlorine percent in the pool calculator if you end up getting the liquid chlorine as it's a higher %, you won't need to use as much to raise to 15 ppm.
Glad you didn't find any dead bodies in your green mess

You can do it! I was also wondering, the hose came off the vacuum head too right, not just the pole?

I've had to pull my vacuum in before with the hose after it fell off.