Kimmy, with all you've been through, consider trying a stronger, multi-strain probiotic. From what I could read about
Culturelle, it has just one strain and 10 billion per capsule. There are many brands more potent--Udo's, Theralac, VSL#3--just to name a few. You could also consider taking more than one per day until your thrush clears. Probiotics should help your thrush, but you need way more than you're getting! (during and after my son was on an antibiotic I bumped his up to around 600 billion from capsules and he was getting an additional amount from yogurt)
Oh, and yes, I just saw what Keeper wrote. I'm going to ditto the Saccharomyces boulardii recommendation. Read your probiotic lables carefully. You may be able to find a combo brand with S. boulardii in it. If not just purchase it separately.
Also, home made yogurt is a great way to get more beneficial bacteria each day (one cup = 700 billion beneficial bacteria!). It's cheap medicine!