as others have stated: something has angered, upset, annoyed, aroused you
this is more of a side note on origin - I suspect the phrase was a spontaneous misquote of a line from the Weezer song "Say It Ain't So" ("...flip on the telly/ wrestle with Jimmy...")

When something rustles your jimmies, it annoyed you or made you slightly angry.

Repositioning sexual organs. For males, repositioning of the penis and testicles. For females, repositioning of the breasts.

Similar to whatever floats your boat, tickles your peach, etcetera.

Another name for the game commonly known as "Hacky Sack".

jimmies – feelings / thoughts / ego
rustled – hurt / disturbed
unrustled – peaceful / calm

As per Know Your Meme, the expression originated from 4chan in late 2010, and is used by trolls to "convey feelings of discontent or discomfort in response to someone else’s post in imageboards and discussion forums".

The expression is an alternate form of "u mad bro?".
 

To plays with other male's genitalia