Could it mean you reconsider your actions several times before actually doing something?
Maybe it's no coincidence that some of the other member mentioned karate. Mars in Gemini also means powerful hands (Gemini).
You might also have a good writing ability and put a lot of passion in your writing.
Ruler Mercury in Capricorn in 5th could also mean talking in front of other people like a stage, for example teaching.
Mercury conjunct Uranus could lead to flashes of pure genius.
I think creating something on your own would be a good idea, you have four planets in 5th house plus North Node there, one of those planets (Saturn) rules the bunch and on top of that is in rulership. Actually North Node Capricorn plus Saturn in rulership is a very strong position indicating a very strong career drive and the need to be successful.
Fifth house is creativity, being on a stage (actor, musician, all sorts of stage performers), dealing with children. Capricorn wants something tangible, something you can touch, initiating (cardinal sign) form (earth), also structuring, organising.
The last chart I saw of a person with a heavy 5th house Capricorn was of a dancer (I can't recall the style of dance), and I think they also won competitions and got medals from there (Capricorn's need for tangible recognition). I personally never thought dancing could be associated with Capricorn but that is also a sign of form (earth), molding what you see into a particular shape, so why not? Further, Capricorn is persistent and slowly but steadily puts all the pratical work necessary to get where it wants to go.
Mars in 10th house (exalted by house) would mean you put a lot of effort into making a name for yourself, turning yourself into someone visible and recognisable.
Mars is at a critical degree indeed which can point to an urgent need felt to express itself. However, the retrograde motion is going to slow down the process significantly. I've noticed retrograde planets like to express themselves in writing or art (more introverted, like talking to oneself) and in Gemini a lot of energy would be dedicated to communicating in some way.
In some forms of esoteric astrology, Gemini and Capricorn form the so-called writers' channel as Gemini is responsible for turning events into thinking and Capricorn - for turning thinking into events. These are the people who cause events to happen, describe them, make sense of them and then draw conclusions.
Your Mars has most probably turned direct by progression about a year and a half ago so it being retrograde in your natal chart should not be something that worries you too much anymore.
If you believe in past lives, maybe there was some karma to pay in relation to you taking some ill-considered actions previous lifetimes.
It being retrograde could also signify you having glipmses of your own future, so to speak, in essence perceiving future and/or past actions as taking place in the present moment. When you get to actually taking the action it might feel like you've already executed it before so you do nothing. It's like time flowing not in a straight forward manner but having glimses from several periods lasting a certain amount of time then kind of having a time jump and moving to another period. Then back in the past, forward in the future, etc.