It could be a different kind of infection. Like bacterial vaginosis.
But, at the same time over the counter yeast infection treatments do not always work.
I would not use foam anymore. It gives me infections so I cannot use it. I also cannot use spermicide as it does the same thing.
So, I would go to the gyno, find out what exactly is wrong and treat it, and then just use condoms and lube. Natural lube, not flavored, colored or the warm up kind.
Some women are just really sensitive. It is nothing to be ashamed or embarassed about, because it happens to a lot of us. Just be careful what you use.