ahh okay, which version of photoshop do you use? I usually avoid flattening things.. i prefer to use adjustment layers, because they are non-destructive (unlike filters) and instead of flattening i usually combine layers into a smart object. 
That way i can always go back anywhere within my workflow to change things later on if i want to. It takes a little more organizing because you have more layers, but once you get used to it its sooo good to have the extra flexibility

(_/)
(='.'=)
(")(")This is Bunny. Copy and paste bunny into your signature to help him gain world domination.