Maybe you are trying to do too much in the ring. Everybody wants to step in and hit and not get hit before landing the huge shot that kos the other guy. But the reality of the game is something different. Also consider that sparring is a work session, a training session, and not an over all assessment or summary of your skills. The simple fact is that your will not be able to fully exert yourself offensively until you are comfortable defensively. You'll be punching from too far away, without setting your feet, pulling your head back and so on. Boxing is a game of pieces and to be effective all the pieces must come together.
You want to develope certain skills in the ring and this is done by sparring; never get in the ring without a purpose. Today work on your defense and countering with the jab. Do the same thing every day until you get it right. Then work on the hook...I digress into my left handed daydreams...The point is this. Focus on something each and every day in the gym and in the ring. Practice is the key and sense of purpose frees the mind in the sense that if you know what you are working on it will come easier. Over time you work on each and every thing to the extent that it all becomes automatic.