It is an extremely difficult thing to deal with sometimes. I know the feeling of not wanting to eat, sleep, work. Everything begins to weigh on your mind.

Sometimes you have to stop caring, or at least pretend to, in order to move on.

I will have to say though, that time doesn't "always" heal it. Sometimes it feels like it has gone away, but the mere mention of their name, running across an old photo, seeing them in passing, etc, brings back a flood of emotion that makes it feel like it just happened yesterday, all over again.

This is even worse, because the worse feeling is not the breakup, but the feeling of "what might have been".

Allow time to heal as much of it as time can, and as suggested, try to do things that distract you from thinking about it, even when you don't feel like it.