It is a hard thing when our loved ones die. You are finally grieving, which is a good thing for you. It is normal & painful & hard, but necessary.
Have you considered writing out your feelings, a note, a letter, a card? Closure is hard won sometimes, but you will have it if you work at it.
Have you thought about doing something in his/their honor? Donating to a worthy cause or volunteering your time as a gift and memorial to them?
There are 7 stages of grief; look up the writing of Elizabeth Kubler-Ross. It may help you through this difficult time.
I wish you only the very best as you work through your sadness.