I had C. diff about five months after my takedown. Luckily I had been doing very well until then so it was obvious immediately that something was wrong that wasn't just the adjustment period, and it was diagnosed relatively quickly. I can't imagine suffering with those symptoms for as long as you have, you my sympathies!
When I started vancomycin for C. diff the first time, I noticed an improvement within the first three days. I had a recurrence of C. diff about two months after that, and that time vancomycin didn't help, so my GI switched me to Dificid, which kicked in within a couple of days. I've had no recurrences since then, about seven months.
I hope you start to feel better soon! If you don't see an improvement with vancomycin, maybe you can talk to your GI about trying Dificid.