EDIT: As per Carboniferous, I have also attached a much earlier save, from 700BC.
I think you should give more priority to improving the terrain, espescially the food.
You should also try to settle near food. The corn/sheep location in the north isn't even explored. I think there should have been time to put a city near the corn SW of the capital
Researching an early religion will slow your growth, and will only start to pay off much later. Researching masonry and building the great wall is a good move on this huge map, but it will slow your growth even more.
researching Iron working and not animal husbandry, and not working a single food resource will slow your growth even more.
The slow expansion problem was however fixed by shaka who put one city where it would be flipped, and he gave a 2nd city away.

Researching iron working so early, without a clear benefit (gems/jungle/attack on someone) will damage your economy. With so many AI, someone should be willing to
trade it for alphabet
Once you have writing, you should built a library soon, and then run 2 scientists. For this you need to grow your capital, and for that you need to improve tiles that
produce food.
I wouldn't want the pyramids here, since there is no stone, and the terrain seems better for cottaging, and there are also no forests left in the BFC of the city where you're building them.
You have 4 workers shopping a forest to the southeast, and you have built 5 mines, but the governor works 3 unimproved floodplains. What you should have done here, is start with farming a couple of flood plains, and only then build some mines, and finally chop the 2 forests in the 3rd ring (beyond that it's hardly worth it)
Your capital is building a worker using the wrong tiles. You get 3 more hammers/turn by using the horse and the 2 mines.
While your economy is definitely a problem at this point, it should be easy to save it with some cottages, and grabbing the marble and researching the aesthetics line and building the great library. (and some more marble wonders, possibly for failure gold)
No one has Aesthetics and a lot of people have alphabet already.
Grabbing the iron/marble spot soon will be good, even without food near, because you'll want some axes with Shaka around.