Only looked at the first save. At this point you still have a tech lead, but you are researching Priesthood, a tech that every other civ in the game is willing to trade you. In fact, you ought to be able to get at least three techs thru trades almost immediately.
Research Code of Laws immediately to build Courthouses.
Also, you need Monarchy ASAP for Hereditary Rule. Trade for Priesthood and tech this.
I'm assuming you researched Bronze Working quickly on a beeline to Iron Working for Praets, but you haven't enabled Slavery yet, in 760 AD. All of your cities are at or above their happy cap and you can use the whip to get rid of unhappy citizens. Slavery gives you one unhappy citizen for X amount of turns, but they're already mad due to overcrowding.
In sum : Trade techs, switch to slavery ASAP. Research COL to get courthouses and whip em out. Then research monarchy to add +1 happiness for each unit in a city; it looks like you have several per city.
Edit : Your workers have done a good job of cottaging the CRAP out of your land. But, building all those cottages does nothing if you don't have the pop to work them. You need to put more of an emphasis on production early on and get them units out to go get more land! You have WAY too many unchopped trees, especially around your capital. Chop out some buildings/units along with the whip and get those cities rolling. You need more than 5 or so mines in your entire empire at this point too.
Edit : Looked at 1780. You need to use Civics. You are still in Barbarism and Paganism, which provide no bonuses to your empire. Also, you are in the civic which gives +50% to worker speed, but your entire empire is improved almost to the max. With the notable exception of Rome, which has a LOT of forest remaining with hills underneath.
Some useful civics include Bureaucracy, which improves your capital's performance significantly, and Caste System, which allows unlimited specialists. These would be much better than what you have at this point. Press F3 in-game to see the civics you are currently in and mouse over to see their effects on your empire. One or two turns of anarchy is a fair trade for the bonuses they provide.
I hope all this helps.