If you worry about your penis's ability to perform, you will be unable to focus in such a manner which would keep you hard and in control. This is because the conscious mind can only focus on one subject at a time. You are either worrying, or applying yourself to fulfilling your partner emotionally as well as sexually during sex.
Over masturbating doesn't cause premature ejaculation or impotency. Make sure you are drinking plenty of filtered water - 2 glasses every two hours, as you may be dehydrated.
There are valid psychological reasons to cut down on your masturbation, however there is no evidence whatsoever that excessive masturbation will contribute to any lasting physical damage to the body.
Hey why not cut down , you will feel the benefit of doing that , just try and take some time out, i know it's not easy but just give it a try ,
Take care ,