So much for just studying tactics

I've done nothing but tactics for 3 weeks. I have played about 12 games in the past 2 days I have regressed. The game starts feeling weird when you don't play games consistently. 

play more

It takes 23 days to master a skill.  Tactical patterns should be seen as their own skill (as in removal of the guard will take 23 days to master, as will forks, etc., rather than tactics wholesale being mastered in 23 days), so mastering tactics in general should take much longer.  I recommend to you read through Averbakh's Chess Tactics for Advanced Players, Vukovik's Art of Attack, and CT-ART 5.0 (starting with CT-ART Beginner then mating patterns) for the practical application. 

You need to practice lots of removal of the guard, (especially) double attack, deflection, etc.  That's when you really burn the patterns into your memory.  You also have opening and positional principles to think about.  When you calculate a sequence you should be at least as well off as before you started.  Some tactics aren't to win material or mate but for a long term positional advantage, sometimes slight, so positional rules and tactics go hand and hand. 

'Internet minded' - I want it and I want it now.

It takes a lot of work before you start seeing overall improvement in your game.

If you are looking for instant gratification, you will continue to be disappointed.  Chess improvement is gradual and take a lot of time. 

Try playing longer time controls, and take more time to look for moves.  You missed some pretty easy tactics in your last blitz loss.  Take for example this puzzle.  It is black to move and win:

I'm willing to bet you solved that one pretty quickly because you knew there something.  But that wasn't even a tactic...it was just a capture.  You're not taking enough time to find moves, and that is probably due to just playing blitz.

I'm just doing tactics and playing against engines the last three months. My achievements:

-A current winless streak of 8 games;

-A rating drop of 115 points (from the peak);

-A monthly performance rating drop of 92 points (from the peak).

So you're not that bad... 

Guys how you are studying tactics. Well i say i am not able to do it myself perfectly but this is advice of my ~2200 elo friends advice. You have to calculate till the end at every problem before move. Problems need to be at least a bit hard for you. You need to get ratio close to %100 as much as possible. Time doesnt matter 5 min or 20 min but you have to finish problem before you stand up. If you tried hard for a problem half an hour passed and still you see nothing (you should have tried your very best) then you can set up a board move pieces until you figure out solution but cant check the answer until you can find it. If you try that way 1-2 hour and still cant find anything you can give up for sure. if you solve 3-10 problems (not the problem count matter the effort you spent (also time) matters) suitable for your level (something like 100 elo harder then your current level) everyday you will feel the improvement in your calculation in 1 week to 2 months (it depends on other factors) Improvement in your calculation doesnt correlate with your elo directly and definetely not correlate with your blitz elo, but in order to level up as a chess player you should level up your calculation first. Maximize your calculation skill first, than practice slow games trying to use every bit of your new calculation skill for some weeks and keep analyzing your games. And you will make your new skill permanent. Than do it again. You will even find your positional understanding, endgame technique and tactics improve just by doing this exercise. I also gurantee you will gain at least 100 elo every year (this is minimum not maximum) and not only you will gain elo but your chess perspective will change, you wont recognize yourself playing half a year ago.

I knew I missed that rook capture but for some reason I decided to threaten the queen first without thinking that it would block the capture

It happens to everyone, but it happens more when playing fast time controls.  Try playing slow chess and use more of your time to find good moves.  You can also try doing exercises like t-ram87 mentioned, where instead of blitzing through dozens or hundreds of tactical positions "based on instinct", you really take the time to identify candidate moves, calculate each one, and then check your solution.  You'll get much more out of it.  

I think at a certain level it becomes more about "training" tactics rather than "studying" them. Studying would imply a cumulative understanding and improvement, while training implies more that you need to train to get your tactics on fire properly again but lack of training and it'll go down. You can only get so far in tactical improvement, you have to have an idea what you want to achieve also, and chess is much richer for it. That's why it's called "the ultimate game of strategy", not "the ultimate game of tactics" or "the ultimate game of spotting combinations".  

great book

i agree, tactics are absolutely useless

i mean only 99.9% of your losses right now are from tactical mistakes

Tactics are simply 1 part of the game.

Ya but you have to play games to keep sharp. I didn't bash tactics training. 

Understanding tactical ideas fully takes longer than 3 weeks. WhenI used to have the time to study, it would normally take a month or two to show improvement... but when the improvement hit I would know it. Just be patient. Its a marathon, not a sprint

23 days: i found this today http://exeterchessclub.org.uk/x/FTP/TacticsCourse.pdf

I agree with Doirse: one of the best pieces of advice is not to play bullet or blitz as a beginner... It seems to have helped me instantly even learn from my losses and appreciate what a good move is..

it is all tactics

It is common to regress after a lot of studying, as you haven't gotten the time to implement the new ideas to your games. Just give it time.