Try not to push them away because they care. If they're worrying it's only because they do care and that's not a bad thing. I bet if you asked them if you were causing them distress they'd say, "No way! You're our friend, we'll always care." I've felt guilty in the past about making people fret, but in the end it's just brought us closer. That's what friends are for! Try and embrace it as a good thing. It is a good thing.