I had a girl that dumped me for stupid reasons and I was much the same until I decided to see it for what it was "a stupid reason" and made myself hate her. For me, it was alot easier to think of her under a bad light than it was to think how "great" she was.
At the time this worked and now later on, I still respect her and understand that what we had was good for what it was, but the pain of the breakup doesnt hurt because I removed all the "miss" factor.
I haven't seen her for 4yrs now, and don't intend on catching up at all.
strange i have tried to hate people but i find it far to exhausting and spend more time thinking about them whilst trying to hate them so i tend to just nothing people now.
after my last break up i was pretty heart broken so i ended up taking up a few hobbies, i started cycling lots to and from work found that whilst cycling i was focused on the ride and thought of nothing else, and i also picked up snorkeling that led to free diving and i found that was remarkably relaxing, see all the cool stuff underwater and focusing on keeping your breathing low and your heart rate down etc.
and from doing all that regularly i ended up getting pretty fit and my abs and body started to get quite ripped so that was an ever better confidence boost as well.
hmm i could use that kind of motivation again now actually lol
but i think every one deals with this stuff in their own way, and its just a matter of finding what works for you, at the end of the day the old cliche of time healing all is quite true, so ideally your just looking for the best detraction to pass that time.