If you see the attachment, you will see the nature of my problem. I have been typing on QWERTY for more than 3 years now after switching back from Colemak and no matter how much practice I get, I still keep typing the same way...
I'll tell you what I tell my piano students.
Each time you make a mistake, you teach your brain to do something the wrong way, and you have to spend that much more time
un-learning that before you can learn it the right way.
So while it may be counterintuitive, the fastest way to learn to do something (or in your case, to be able to do it again) is to do it
slower—slowly enough that you don't make mistakes. That may mean crawling along like a snail. But however slowly that is, that's what you should do—because in the long run, mistakes cost you more time and frustration than you'll ever save by continuing to make them.
Once you can type at a steady speed without errors (and again, however slow that may need to be), start nudging your speed back up, allowing your skill to reinforce itself. If you find you're making mistakes, slow back down until you don't. Repeat as needed. The key is to avoid mistakes by not trying to type faster than you can, you know, type.
And very importantly, resist the urge to beat yourself up—calling yourself an "idiot", etc. All that does is reinforce the belief that you can't do the thing, or that it's harder than it actually is. Your unconscious mind can't tell the difference between reality and fantasy; it just observes and obeys. Each time you make a negative statement about yourself like this thread's Subject, your unconscious mind says, "Okay, that must be true, got it!" And your life gets that much harder. So stop
doing that, okay?
Just take your time, do it right, be patient, and know that you'll eventually prevail. Cheers!