downswing has lead to terrible play, help please!

[tuckercat]

i hit a pretty rough 15k downswing playing 60% 3/6 and 40% 5/10 NL over 15k hands... i spent quite a bit of time going through my PT stats and honestly trying to assess my game, and wtf has really been going on during this downswing. with that said, i've come to the conclusion that although i've been running worse than horrible, i've made a ton of horrible plays...mostly i've been passive in the wrong spots and checking when i should bet. i've lost a ton of value bets, and what's worse is i've let a ton of hands get there. my sessions have had the same trend, i.e. lose with KK to TT on a 9 high flop, and the first thought that goes through my head is "here we go again". so my first instinct in to curtail my aggression, and play like a bitch. for example, i just finished a 2k hand session, and lost $340 5 tabling 3/6...the loss is fairly insignificant, however the manner in which i lost is significant. this session started off like all my sessions have recently, i lost with KK vs AK preflop for a standard 200 bb pot. then i picked up QQ and lost to JJ on a J high flop for another 200 bb's... then i recovered somewhat, played very nitty and somehow got paid off a couple times. however, in the mean time i won the bare minimum with AA vs KK on a Q high flop because of my fear of running into another set as i had already earlier in the session. needless to say, my mind is pretty throughly messed up and i'm totally off my game. aside from ranting, i was hoping to get some advice on what others do to deal with this kind of thing. how does one go about being totally indifferent to bad beats...and how does one go about totally disregarding that he's running bad (or atleast that he perceives himself to be running bad). this is a massive mental obstacle that i've hit that really has me questioning myself as a poker player. i've always been a winning player, and have NEVER doubted my abilities up until this point. any help or suggestions would be appreciated.

cliff notes:

OP hit a sick downswing and is mentally screwed up. seeking advice on how to overcome said current situation.