Don't panic. Aptasia is not the end of the world, its a nuisance. There are many threads on this website that deal with aptasia so you can read them. Most will advise you to inject with Joe's Juice, a lemon juice mixture, etc. Think of them as weeds in your garden, you just have to be vigileant in plucking them out. (Don't try to pull the aptasia out with your fingers- it just disintegrates and forms in numerous other places.)