This type of night fall depends mainly on the age and the health of the person. In young age group there can be much variation in number of night falls.
Now another important thing is that you have to understand is that this is a natural phenomenon to get ride of the production of semen in the body and this is not going to harm you in any way.
Only thing is that you have to get your energy to be used in a proper way and try to concentrate on some constructive work. Try to engage yourself in something which you enjoy and keep this thought out of your mind.
The main problem in this case is the anxiety
associated with this type of situation and if you can control your anxiety, than you will not have any problem.
Thanks and take care.