Josh,
Second thoughts are normal, just like pre-marriage jitters! Don't feel like you are being disloyal or anything.
If you spend all your time saying to yourself "I'm so miserable in KA, I should have chosen Phi Psi" then quit. But if you are enjoying KA in general, then stick with it. Stay friendly with the Phi Psi's - just because you aren't brothers doesn't mean you can't be friends. That way they know it's nothing personal, just that you chose what was best for you.
