Singapore has a relatively low voluntary blood donation rate because many people are apathetic, afraid of blood, ineligible for various health reasons, etc. Blood stocks tend to be low at the end of the year and there will probably be a public call for more blood donors soon.
I've been a regular blood donor since my undergraduate days in NUS and will encourage you to be one. If you are an NUS student or staff, it is very convenient to donate blood. Just head to the NUH blood donation centre which is next door.