Got to agree with Bose here.
This has already been said here many times, but it is worth re-iterating. Chill out!!!!!!
In life, as a whole, the best teacher we have is experience. Some we take out ourselves, some we glean from others, but experience is it. Nothing else will teach anybody anything.
I appreciate that you are one of those people that works hard to acheive goals, and that is admirable, although I have to say that in my opinion, any fool can work hard, the clever guy works smart!! But that aside, experience is the only teacher we ever have in life be it ours or someone else's.
That is why you need to chill out, you cannot work a bit harder at this game. If you push harder at work for your goal then you will acheive it, but remember this, at work you are on terra firma and it wont kill you if you disrespect it! What you need to gain is experience and lots of it. As you have said the last lesson went better than the one before, the next one will go better again, and so this will carry on, that is why we have an hours limit in aviation, so that you not only have the skills at the end of the course, you also have a reasonable level of experience. Don't forget that a ppl is a licence to learn though.
Remember learning to drive?? After about 3 hours you could probably drive in a straight line and turn corners and make gear changes, but you had to think about it didn't you. Did you always drift left or right a little when putting the indicator on?? I know you did, all learners do, bet you don't do it now though, and change gear without even giving it a concious thought. That is because you have experience as a driver. Don't believe me?, try driving a left hand drive car for a couple of days, you will have to teach yourself to drive the wrong way round and your brain will hurt for a couple of hours whilst you get used to it, and that is what is happening in your aviating career.
There is nothing you can do about it, accept that you have to chill out, and it will fall into place a lot quicker. It is surprising how much more you enjoy it when you aren't under pressure you know!
And whatever else, along with other here, take our advice and don't quit. You will forever kick yourself if you do, trust me!