I am willing to bet you've got quite a few leaks in your game that need to be plugged up before moving up limits....
I'm not saying this to be mean.... I am saying this to help you out.
If you really think you are a winner, then by all means go for it!
And good luck! (I'll even come cheer you on in a sit-n-go

)
If you keep losing and think you are playing strong poker, then maybe you have more to learn.... (Everyone always has something to learn, no shame in that)
Good luck either way.