Tips to not feel guilty about masturbating?

I don't know why but every time I masturbate, I feel guilty afterwards. Normally I don't even begin to do it when I'm in the mood because just the thought of feeling guilty afterwards makes me not want to do it. It's like I'm afraid something bad will happen in my life if I do it...like I'll get bad luck and then something really bad will happen to me at school or something. I don't know where this "fear" came from. Nobody ever told me it was wrong or shamed me for doing it. Anyone have any tips to help get over it? I know it's a pretty common issue so I feel like someone had to have dealt with this in the past and found ways to help with the negative feelings.