The first time it happened, it wasn't a romantic heartbreak but that doesn't make it any less devastating. I shut down my feelings. I didn't feel good or bad, I just carried on and told no one. I kept trying to maintain some kind of relationship with the person but it only lasted a couple of desultory years. It was horrible.
The second time was a romantic heartbreak. I cried for the entire 8 hour drive from the apartment we shared to the city I was moving to. (I'm not a crier) Then I drank and went crazy for a while. (to be fair, I'd been drinking every night for the last 6 months of our 2 year relationship) I went to work every day and did the shopping and fed the cats, but I was completely nuts. I thought people could tell just from my face that I was completely destroyed and were avoiding me because of it. They were probably avoiding me because I had a constant angry face, wouldn't/couldn't make eye contact and when I did have conversations they were very weird.
The third time was weird. It was a romantic heartbreak but also something else. I don't even know how to describe the relationship without sounding crazy. I was obsessive about him during the relationship and then after the split, I became equally obsessive about security. I don't think I really believed he would ever try to hurt me, but I needed to have barriers just in case. Oddly, he was the one who broke it off but in later conversation he seemed more angry/hurt than me, the dumped one. I feel like I'm emotionally over this one, but I'm not sure how true that is. 