[golFUR]

Though already noted I'll contribute my two cents in different terms for perhaps a different theoretical understanding.

The situation you describe occurs several times in a chess career and is responsible for a lot of people quitting just as they get going. It is common enough that you can predict at what points a player will start losing.

When a player first begins playing, depending on natural aptitude and mindset, they are going to quickly settle at a skill level between 900-1200 (on a scale of 3000 or so). While results may vary, this is a close approximation. With continued study and play they will progress up to the 1500-1600 range, the first plateu. Here begins the first losing streak and culling process. Many players assume this is as far as they will go or give up in frustration at the sudden string of losses coming so soon upon the heels of what they felt was a great learning experience.

Moving up a level is like suddenly seeing behind a veil. A lot of things you didn't understand are now clear, distractingly clear. You become overfocused on new variations or techniques while disregarding fundamentals.

If a player makes it past this stage they will progress to the 1900-2100 level, the second plateu. By this time they are more familiar with the phenomenon and generally have less difficulty with it. There is still the same observable traits though, many players stop advancing around this level. A new understanding, a refreshed love for the game comes at the same time as a losing streak. It seems wrong to suddenly be losing when the game suddenly makes so much more sense.

Play through it. Remember the fundamentals, add your new tricks to your bag slowly. Be aware of the deeper levels or currents but don't exist solely in them.