possible for winning player to become permanently losing?

[ozdg3nr8]

background...played 300k hands of poker winner at all levels up to 5/10. i have 120k of winning hands at 5/10nl winning at 1.8bb/100
11 consecutive months of winning approx made 80k,
the last two months i have been losing/breaking even over 100k sample. i have made about 2k in this timeframe.
i have lost complete confidence in my game and every time i start a session i just feel like i cannot win and i am bound to lose.
is this merely variance? was i just running good? have i developed leaks?
i just dont know what to do, it doesnt seem like it will turn around no matter what i do, i have thought about quitting as playing severely messes with my mood.
thoughts?