This is so interesting! I love brevity in poems for this very reason. There's a great deal to be said, and readers can interpret it however they like and still not pinpoint exactly why you wrote it, as there is some mystery to it still.
Pockets on clothes makes me happy, especially dresses! I think there are people who use pockets and only view them as storage, whereas, others may simply like to have a place for their hands, or to place nothing in them at all. The mention of the pocket feeling heavy... perhaps there are objects you are collecting, or memories with weight, and just knowing that you have some place of security is reassurance enough.
Really neat write, and I'm glad these 13 word poems have helped clear your mind :)