So is this a sudden problem, a new issue for you? Or is this just how it has always been to be you? You used the term "sudden disappearance of skills," but you also indicate that this was a problem for you during your 4 years of high school.
A new problem could indicate that you should see a doctor. It might be a physiological problem that recently developed.
If it's business as usual, then one of two things could be operating, depending upon the severity of the problem: 1) you might need to see a specialist in executive functioning, though I'm not sure who specializes in that area; or 2) it might just be normal.
I'll defend normalcy: I often feel like I could do more if only my brain would keep up with me. Especially if I'm thinking about other things or stressed or not getting enough sleep, I forget things or make mistakes like the kind you're describing. I don't think that's unusual.
Sometimes things seem hard to me, and I'll work on them for a while. Then I give up and walk away, only to find that I get it very quickly the next time I look at it. My theory is that my subconscious keeps working on the problem after my conscious brain has given up and gone to bed. So it's not that my conscious brain isn't working, rather that my subconscious mind works extra well! I have just used this to my advantage: study the hard thing before bed, then study it again when I wake up. My "click" moment usually kicks in pretty fast in the morning. Not always, but usually.
I guess I'm saying that while there might be a problem for you that requires attention, I'm not 100% sure that what you're experiencing is unusual. The general ability to learn new material easily that accompanies GTness does not mean that you'll have an easy time learning *everything*, and it doesn't mean that you'll learn it on the time frame that you wish. Nor does it mean that you won't forget where you put your keys or what you had for lunch earlier in the week. Some of that is just life as a human being.
I feel like you're assuming that GTness equal perfect performance, and that's not the case. (No offense intended!) We all still have bumps and glitches in our daily lives. We just work around them and do our best.
HTH!
