I'm guessing you've taken an EQ test to know your EQ is low?

You actually come across as very insightful in your posts and your 3rd paragraph reveals a deep insight into yourself. I think many people with low EQ do not have the insight into their own behaviours so you have a head start there. I would suggest that when you find yourself acting on your frustrations you stop yourself and try to imagine the situation from the others perspective. Empathy is mainly understanding the other persons view point, being in their shoes, in fact it is quite a logical process in that way.

It's interesting you say you used to be more sensitive, it sounds like you made a choice (albeit maybe unconscious one) to switch off that side to protect yourself. So you are not starting from nothing, you are reconnecting with another part of yourself.