How do I get out of Middle Age Standstill/Slump

I love to play civ i always start a new game with big expectations, and hope for a awesome game.
But i always slow down anything im doing around the time of the middle ages, usually i slow down in TECH, Econ, and expansion.
I kinda just let turns go by until i get sick of doing the same thing, so i usually go out and try to conquer other neighbors but then i capture a few cities then i am effed because they always seem to come back even stronger, then i lose a few cities more then i started with.
This goes on until i research early industrialization techs, then i try to regain my once great supremacy over everyone.

So my Question is "How can I keep increasing all attributes of my civ and keep my self from feeling trapped in a stand still?

This is quite common and that is why I wrote the Regent tutorial in my Sig. The issues are mainly
1) expansion is not fast enough or large enough
2) lack of workers
3) too many structures that are not critical, at least at the time they were started
4) too many defenders
5) wide town placement

Not a big issue is micromanagement. You hear talk about this, but to me it is over rated. Yes if you are playing against a record, a personal best or something. To deal with Monarch or lower, you only need to not let the gov run things completely and watch for the big stuff.

That is towns not growing, towns about to riot. If you can toss in some movement of citizens from tiles that do not match your need from time to time, that is a bonus. These occur after grow.

If you post a save then the game can be review to see if those are the issues or there is some other problem.

Let me add another point to vmxa's list of main issues:

6) lack of contacts and/or being an unexperienced trader

The reason is the following: the Ancient Age techs are still "affordable". Once you have set up 6-10 initial towns, you should be able to research the average Ancient Age technology in a reasonable time. (Unless you are playing Emperor and above or huge maps...) However, with the advent of the Middle Ages, tech prices double (or even tripple in some cases?!). So unless you have an exceptionally well-developed empire, research becomes painfully slow. So slow that it feels like a standstill. And the only way to get around this is having many contacts and doing some skillful tech trading.
So if you are too weak to wage a successful war with your neighbors (which from your description seems to be the case, otherwise the AI won't be able to recover from your blow and even strike back), then don't go warring! Instead treat the AI as nice friends who are there to help you... (Until, thanks to their help, you caught up and pass them by...)

Lanzelot

How can you be a good trader? It seems to me that no matter what I do, the AI always have the winning side of the trade.

You have to first understand the value of an item to them at that point in the game. If you are looking at a lux deal, they consider how big your empire is and how many lux you already have.

If you are playing OCC and have 1 lux, you can get a lux cheap. If you are the largest in the game and have 4 lux already, you will have to pay and pay.

Techs have to be calculated for the beakers required in that setting. If it is 1000 beakers and you want to give them a 400 beaker tech, it had better have something special to come with it such as a new wonder/gov/unit.

If not why trade? They also factor in the bearkers they have in the research already, if any. IOW if this is a 500 beaker and they have 10 turns research on it, they will want a reduction in the price. The cost is reduced, if they know others that know it, reflected in CAII.

These are the main things you need to understand to evaluate a deal and the fairness of it. I do not really think there is a winning side. It is just does the deal makes sense to you right now or not.