I could be totally wrong - but if you make a lot of milk - it might be longer to wean. In my case - I was pumping enough to feed DD AND to freeze a couple of bags a day. It would have been hard to for me to wean that quickly. I was thinking about this after your post - it might have not taken me an entire 2 months but it did take me a couple of weeks.
Also - I think there's a difference between weaning from pumping and weaning from BFing. When you're weaning from BFing - you're already in the process of weaning because the LO is eating more and "drinking" less - so the woman's body must have been prepared to wean completely. When you're pumping - there's no tapering off, etc., so you have to do the tapering off for your body. Also - consider - you not only took it in 5 minute increments - but you adjusted the speed as well.
Anyway - I could be totally wrong... :/
Hope you find some relief soon....