Selenium Sulfide to slow shedding?

I've been in a constant state of shedding pretty much since I started to loose hair. But now, its at a point where I am shedding too much. Like 40-50 hairs in the shower and then another 20 when drying it.

There was a thread on here about someone who stopped their shedding using a zinc-based anti-dandruff shampoo. Immortal Hair mentioned that the shedding could be due to a yeast growing on the scalp and that an a Selenium Sulfide topical could kill the yeast and stop the shedding.

I was thinking to try Selenium Sulfide which is the main ingredient in the shampoo Selsun Blue. Problem is that there are too many harsh ingredients in the shampoo that could easily cause more inflammation.

So what do I do? Is there a Selenium Sulfide shampoo without any harsh ingredients? Is there pure selenium sulfide I should just use as a topical?