Doesie, i feel exactly the same as you sometimes.
I can for sure say that ive become a much better SNG player now then when i started last year, but im still struggling to make it profitable.

I have a great day playing SNGs and win alot. I feel good about my game, knowing i probably am on the right way. Im patient, dont take unneccecary risks, and dammit, i place in the money in most of them!

The next day, i do the exact same thing (this might not be true though as it might very well be that im lowering my guard without knowing it. Still trying to figure it out) but cant even get in the money.

So (allready on tilt, not knowing it) i start modifying my game trying to find the same way to play as i did the day before. This, of course, ends in total disaster before i understand that im on tilt.