On the other hand, its better to indulge in this 'bad habit' than to resort to alcohol and other drugs to overcome nervousness (if thats what really helps).
You may be addicted to masturbation and probably feel its your only way of solving your inner stress or problems. On the contrary you may be suffering from anxiety attacks. it all depends on the job occupation that you have or the events you go through your day to day life. For majority of people, masturbation is a way of relieving stress for them. But it is a bad habit. Best way to control masturbation is to do different activities that will keep you busy and help keep your mind at ease and off sex. Try going to the gym , or doing some form of exercise that will keep you busy and will leave you feeling tired...or best get a sexual partner so you do not have to masturbate...and play it safe if you do.
Doesn't a smoker who doesn't smoke for three days get a jittery feeling too?
Sounds like it's a body side effect after three days of no masturbation (if you're body is use to masturbation every day).
For me, my testicles feel discomfort unless I masturbate daily. But if I let a good week go by, the feeling will go away. So your nervous feeling should go away in a few more days (if you choose not masturbate)