I don't think you should try to play MORE. Instead I suggest that you, actually, play much less for a while. My recepie for you is 15 minutes - set a timer! - two to four times a day. After those 15 minutes, you have to leave the piano for a while.
This is not forever, of course, but for a period in order to make you more focused. With such a limited time, you are forced to be much more effective. Plan your sessions in forehand, by making a little journal. Evaluate your session afterwards and make a new plan, and so on.
Stop blaming yourself. That is forbidden! Instead, you should make a summary after each session: what did I do good/better this time? You MUST find something every time, that is very important! The point is to set you in a better mood, that will make you more motivated. (Believe me, it works!) Once you are highly motivated and eager to work, you can focus on working with mistakes that hang on - or rather, focus on working with improvements.
For fun, you can imagine that you are a mega super star, a real pro, working diligently on your daily tasks. You should feel calm and confident. Difficulties are fun challenges, and of course you will solve them all. And that is all you need to know! DO NOT WORRY!
You see, I have been there. I sometimes wanted to kick myself somewhere ...

And the result? I played worse and worse. So I know that the problem is in your self confidence. You make the piano a place for "being whipped" - it does not matter if the critic sits beside you or inside you, you will feel the pain and you will get tense and afraid of it - the result? You play worse and worse. And soon less and less ... So you have to reverse the process, make piano playing a "success story" where you can feel happy and confident instead.
Some other more practical advice: find the blog and e-books by Graham Fitch, where you will find a lot of valuable advice on how to practice.
Record yourself often and listen to yourself often, while you are taking notes and make decisions on what is wrong and what to do about it. Uneven playing? Practice short segments slowly, work on being relaxed. There are different techniques to use - see above about Fitch.
Practice more mentally, reading sheet music away from the piano, listen a lot to other pianists. Try other genres, perhaps a little jazz improvisation or composition could be fun? I think what you need is a feeling that you are effective, that your efforts pay off again. And I think you need to relax and feel positive about yourself again.
Good luck!