Ale is cloudy and really fizzy

I think the most likely cause is not overpriming, but that you bottled it too soon. Even at as high a temperature as you used, it's pretty unlikely that the beer was finished fermenting in 6 days. Even if it was, that's not enough time for yeast and proteins to drop out and the beer to clear. I highly recommend keeping it refrigerated for 3 reasons...first, if it wasn't truly finished when you bottled it, keeping it cold will reduce continued fermentation. CO2 also goes into solution more readily at cold temps, so it may be less fizzy (although it may not). Finlly, keeping it cold will help all the stuff in the beer precipitate and fall to the bottom if the bottle so you can leave it behind when you pour.

Carbonation

I agree with @Sander's recommendation to use an online priming sugar calculator. I respectfully disagree that carbonating in bottles is an art -- it is repeatable science.

One way to get close enough to moderately carbonated beer, but not necessarily precisely what the styles calls for, is to use carbonation drops, Coopers tabs, Prime Tabs, etc. These are basically sugar lozenges.

Otherwise, the key is to understand the process, and to disregard your kit's generic instruction on priming sugar amount. For equipment and supplies, you need a one gram-resolution scale ($10 in the U.S. from Amazon), a mixing spoon, some pre-mixed sanitizer solution to sanitize the spoon, and some sort of sugar. It is almost essential to have a bottling bucket with spigot that you have pre-calibrated.

You can calibrate a bucket by marking graduation lines for every quart or liter (fill with water, mark a line, repeat). You only need to get to quart/liter increments when you are near your standard batch volume (e.g., for 19L batches, I would mark from 15L through 21L, and in 5-liter or one-gallon increments until you get there).

In my opinion, refined white table sugar (sucrose) works best for priming because it is cheap, readily-available, pure, and reliable. But dextrose aka pure glucose is OK too.

You need to know your exact beer volume, the highest temperature that your beer reached after the vigorous stage of fermentation was over (roughly when krausen drops), and your beer style. Plug these into the online priming sugar calculator. It will give you the precise amount of sugar to add for your type of sugar.

Weigh it out. Do not measure it by volume (cup, teaspoons, etc.). Boil this in a small amount of water. Half a cup is usually enough for me.

Now thoroughly mix the sugar water into the beer. It takes more mixing than you think, or you will have a batch of flat bottles and bottle bombs. But it is absolutely crucial to stir gently so as not to make any splashes, waves, or bubbles.

This is why you want a separate bottling bucket --because this process will stir up all of the sediment, which is not part of the beer. So how will you exactly measure volume? Do you want to add that sediment to your bottles?

Clarity

As far as clarity, you can look up ways to add finings to your beer or to achieve clarity in this forum. Use keywords finings or clarity in your search. You can cold crash your beer by putting the fermenter in a fridge or cold location to speed up clearing of suspended particles.

Clarity is not necessarily a sure sign the beer is done, but it is one sign. When the yeast drop out of suspension, then you have a clue you are closed to finished. If you bottle the beer to

Another possibility is that you got old or bad cans of extract -- I experienced a persistent haze using old cans back in the 1990s.

Yet another possibility is that you are bottling with a lot of sediment and/or disturbing the yeast on the bottom of your bottle when you pour, making you beer cloudy. Look up "how to pour homebrew".

Firstly, welcome to the world of brewing! There are so many different parameters that can cause so many different outputs of the beer that it is very difficult to pinpoint exactly what you did, caused what output.

The problem with it fizzing is most likely over-carbonation. From my experience it takes a while to master how much sugar to put into the finished product, to give just the right amount of foam and carbonation. I have had batches that have had exploding bottles in my storage, to beer that hardly even has bubbles in them, practice makes perfect. In order to get the right amount use a priming sugar (the sugar put into the bottles to produce carbonation) calculator; example here.

Now, clarity is not a very good pointer to whether the beer is "done" or not. If you are done with fermenting it, and have left it in the bottle for a few weeks and are happy with the taste, then I would call that done. Having cloudy or opaque beers is not uncommon, look at many commercial beers for instance, and are quite common when homebrewing due to the lack of filtration. If you insist on having clear beers I would recommmend trying Irish Moss when brewing (or something similar, your local supplier can probably help you out).

Kits are not really a waste of time, they introduce you to the magical world of homebrews and are great stepping stones to becoming a master brewer. In order to get a bit more wiggle room for different hops and malts I would quite quickly move on to brewing with extracts or steeping. A great guide to getting started with either one is How to Brew.

Best of luck!