Kate,
don't count on that time limit. Everyone heals different and has different timeline. It's not how long relationship was going on - it's more what this relationship meant to you and how deeply were you in love. Don't make time assumptions - you'll be pretty disappointed when it does not "end" when you expect it. Everyday it will be a bit easier (maybe you will not notice it - specially at the start of it). I've noticed (I'm 5 months after BU of 3,5 years relationship) that first month or two, actually thing were getting worse, but they started to be better. I had a setback on sunday (saw my ex kissing a guy she let me for) but now I'm better. It will pass. It will take it's time but it will pass.
Just keep going...
Okie