maggie, i'm sure they'll sort it out in time for your op, you have a couple of months yet.
when i had the pre op tests for having my first hip done, my urine sample kept coming back 'contaminated', time and time again. the surgeon said he wouldn't go ahead until i had a clear sample, and like you, i was completely devastated. my gp put me on a very high dose of antibiotics for 3 days, and that did the trick. why it kept saying 'contaminated' and never 'infected' i have no idea.
with the second hip, it was blood pressure. never had a high reading in my life, then at the pre op. tests, same thing - far too high to go ahead with the op!! gp started me on blood pressure meds and managed to get it down to an acceptable level for the surgeon, so the op did go ahead.
so, i do understand how you're feeling, but as i say, you have plenty of time to get it sorted out. i'm sure they will do all they can to ensure that you have the op when it's scheduled. but if not, then better to be safe than sorry and wait a little while longer. these tests are done for a reason and your surgeon is the best one to decide if it's safe to go ahead with surgery.
keep your chin up maggie.
sue