Can denial be used as a defense mechanism after a break up?

ok so i've only been a psychology student for about 3 weeks but i'll try my best :p as far as i know this can happen and i imagine it happens because the mind doesn't want to believe what is happening so you just go into denial and ignore everything that's happened. Even though you're telling yourself it has happened there might still be a part of your mind that doesn't want to believe it. about 4 years ago now one of my boyfriends dumped me and there was a short delay until it dunk in. i just fell asleep not worrying and woke up really upset. maybe this is the same with you just more stretched out...sorry if this is no help at all xx