Exactly as The Eagle said. In your mind you surely are sympathetic. If you bring out your sympathy with actions of sympathy, you will be sandwiching your emotions between two sincere attitudes. Eventually, your emotion will join the choir.
There is no point in working yourself up just for the sake of being upset. But, if you feel that you are being too indifferent to someone else’s plight spend some time pondering what the person feels and which different parts of their life are affected by what happened and in what way.
Realize though, that it is normal that as your life gets busier you concentrate less on other people. However, as your own family grows you learn to care for others. This is why the Halacha is that we try for the Shliach Tzibur on Yomim Nora’im to be someone with children.