Is it just me who’s feeling this way?

I was adopted in S.A in 2008 and was born in 2007, my biological mother abandoned me and there’s no way of me ever being able to find her as I didn’t have a birth certificate and wasn’t born in a hospital. I love my parents, I have an older sister who isn’t adopted and is my parents' biological daughter. Today I was looking around for a few photos and found 100s of photos and pictures of my sister when she was born and basically the 1st year of her life. I know that I’ll never be able to have those because I was only adopted months after my birth, I know my sister doesn’t remember the first year of her life but my parents do and watching them sit there and speak about something I’ll never have hurts. Even though I’ve gotten older and gone to therapy and counselling, I’ve never had to deal with a situation like this where I feel like something was "taken" but never "given" to me..