Hi Lilypad
I understand your worries over changing meds.However,if they are no longer effective for you it really would be a good idea to take the advice to try duloxetine.
I too couldn't take fluoxetine-it made me very sick and dizzy, and as a busy Mum I had to stop taking it.
I swapped straight over from a ssri(sertraline) to a snri(duloxetine) with no problems.I had a dry mouth and was a bit tired for a few weeks,but it was a small price to pay for the enormous relief I felt to feel better!
You are lucky to be offered Duloxetine, as it isn't prescribed often here due to the cost. For this reason I would say give it a go!
Of course meds work differently for everyone and it really is trial and error to find the right one for you.
Keep us posted as to how you get on.
Good luck
Loreen x