Pfalz Open 2018

Well, I won against all players rated lower and lost against all players rated higher - a pitty, that this still makes me lose some rating points. Although, in the very end, it is well deserved!

To cut it short: I need help!  Why on earth do I fuck up positions like the ones below???
(Let´s face it - within EVERY of the last 5 tournaments, I have similar positions being totally won. But in the end I don´t manage to get the full point, often not even half of it!)

From move 11 to move 30 I was holding between 1.1 and 2.8 plus. Here is the position, where I fucked it up completely within two moves - I was White, against a 2222-guy:

 My gut-feeling told me that I can take on b6 - but I didn´t have the time to calculate it. (Black played an incorrect piece sacrifice earlier on and actually there were three interesting and - according to the computer - winning replies to it. I saw them all and calcuated them all, costing me some 30 minutes. That´s why I ended up in time trouble.)
I also could have taken on d4, but, hey, this would have also won the game!!!
Soooo, I went for Nc7 which is still winning, but within three more moves I threw it all away!
The only good thing: I had 3 times the chance to force the exchange of Black´s three pawns versus my pawn+knight - leading to a dead draw. But since I knew that White is definitely winning, I did NOT chicken out; at least not.

Here´s another one:

So I kept this 2175-dude off my neck for over 50 moves and I was absolutely convinced that the above position is a draw. But yet again, I only had seconds to think - and lost!


This is so demotivating and annoying (if I would have won the first game above, I would have scored some 15 ratings points)...