Why can’t I feel love like others do?

To answer your first question regarding how you are mourning your father's passing and wondering if there is something wrong with you, my answer is no, there is nothing wrong with you. Everyone mourns the loss of a loved one in different ways and some people feel the loss more deeply than others. The intensity of the feelings regarding the loss also varies from person to person, as does the length of time. I would have to know more about your sister's and your's particular experience with your father and both of your feelings of loss to know for certain if what you experienced was normal grief and if your sister is experiencing complicated grief. There is no known cause for complicated grief, however, if your sister was your father's caretaker or was there when he passed or had a dependent relationship with him, these are some potential reason's why she has grieved longer.

To respond to your statement of not believing in love and feeling that "love" has less of a value than "to care" for someone; what are you basing this thought off of? Is it because others have told you, you must not have "loved" your father because you are not mourning the way they would have? I want you to think deeply about what "love" means to you and what does "caring for" mean to you. Being loved may often mean the sentiment comes with words of affirmation of that love; lot's of "i love yous". However, being cared for is more of an action which means someone will perform acts of service for you as a way to show they care. They may buy flowers or bring food when you are sick or just listen for hours as you ruminate over an anxious thought. Is it possible that you look at love from a different lens and believe love means doing and not just talking? If yes, then that may be your main love language and is it possible that any past partners you have had, did not speak your love language? If so, keep looking for that special someone who shows their love with acts of service. I hope this was helpful!