How can I unclog this toilet, I just tried a toilet brush. Will just letting it sit for a bit help, I know it is just fecal matter that has clogged it

Go out and buy a toilet plunger... thats what you need.

Plunger is the BEST tool to unclog blockage in toilet bowl. Also, you can use 5' auger that will accomplish exactly the same - but with less effort. Toilet brush is not a tool used to unclog toilets.

Back to you / Milo

EVERYONE should have a plunger in their House... Condo or apartment... because things sooner or later will get temporarily plugged up... they are really cheap... and easy to use... and they don't take up much space.

And it is normally paper or at times other objects. Grease from kitchen may also clog drains,
There are many reasons for it. But toilets get clogged often, and a brush is for cleaning, not clogs