It is hard, very hard. I lost both my parents within a 3 months, and it does leave you feeling like an orphan- and very aware that all our times are limited.
How old are you, and how old were your parents when they died? I was 60 and they were 94 and 96. So I count maself so lucky that I had them all that time, even if they lived far away. And that they had such an interesting and loving life (although my mother hated the last few, blind, and totally dependent).
But that is the nature of things. It is normal for us to lose our parents, when they have reached a good age. That is our nature intended, of God if you are a believer.
Losing a parent young, when they are young- is another thing. And losing a child, at any age, is beyond cruel and beyond sad. This should never happen, and this is something that many, totally understandably, will never recover from. Several of my friends and my young GP are in this position, and are finding it so hard and so painful.
I wish you the best to be able to come to terms with nature as it is intended, and accept their loss, however painful it is.