Oil pressure

Ain't drove my car in a while reason being is that on cold start up the pressure would be around 5.7 kgcm2 then drop to about 0.9 sometimes slightly lower, I've read that on startup it needs to be at around 6 and around 1.1kgcm2 which mine isn't, I have a spa gauge which is suppose to be really accurate and I've ways used 10w40 never had issues with oil before, is it time to change the pump over?? Any advice would be great