Emotional on/off switch

So this is subject I've tried many times to look into and I've never really found as satisfying answer. 

From as long as I can remember I have had the ability to switch off my emotions at will. So much so after many years of doing so and beginning to better understand my emotions, I began to be able to compartmentalise my emotions and switch them off individually. This was great for times when I'm focused and active because it allows me to block sadness and still feel an anger which motivates me etc. 

But when something like a relationship breakdown, loss of family member or other major trauma I switch off completely, I'm still me, but I'm withdrawn, on auto pilot, I do the things I enjoy, but not because I enjoy them, but because of time. I feel nothing so I become very aware of time. Shutting off doesn't mean it's not there, when I want to switch it all back on, it's an open floodgate. 

Does anyone else here the ability to do this? Is it a childhood trauma response, is it autism related?  

To many people the idea of this it's not great, but the reality is to do this emotional yo yo, I have to open a floodgate which usually sends me into a shutdown, which I never come back the same from.