How old are you? Still in NS that means around 20's? And you are
already behaving like you are missing your wife or what.. Anyways,
you are supposed to be a man, stop being sissy and crying in
toilets. If people are doing well around you and you are not doing
as good as them, then whose fault izzit? Is it because of your gf
not being around you? Think about it. Doesn't it sound stupid? Can
you only perform well when your gf is sitting beside you?
Alrite, given that you are not able to concentrate at all on your
stuff due to your lack of knowledge about where she is, does she
know how you are feeling? Does she know that you are suffering so
much? If she really loves you then why she is doing this to you?
Can't you ask her to keep in touch with you, update you, inform you
which days she will be in Singapore and so on, so that you can plan
and have at least something to look forward to?
In any case, you should grow up bro, you can't be weak like this.
You should develop more will power and learn to concentrate on
things instead of being distracted by other matters. Like this you
won't even excel in studies (if you are planning to do further
studies).
Do yourself a favor, be a bit selfish, work hard for yourself
first.