A question about masturbation?

Does cause you to be anxious the next day. Is this anxiety i feel me feeling guilty? Cause consiously i don't feel guilty but i was wondering if its possible that i feel guilty subconsiciously. See, I have this dusche bag grandma that is a bigot catholic and she says masturbation is evil. I know it won't cause blindness or anything and is not evil but i guess my question is, are there any side-affects to masturbation that have been proven or that you think is valid?